NAME

Astro::App::Satpass2::FormatValue - Format Astro::App::Satpass2 output as text.

SYNOPSIS

 use strict;
 use warnings;
 
 use Astro::App::Satpass2::FormatValue;
 use Astro::Coord::ECI;
 use Astro::Coord::ECI::Moon;
 use Astro::Coord::ECI::Sun;
 use Astro::Coord::ECI::Utils qw{ deg2rad };
 
 my $time = time();
 my $moon = Astro::Coord::ECI::Moon->universal( $time );
 my $sun = Astro::Coord::ECI::Sun->universal( $time );
 my $station = Astro::Coord::ECI->new(
     name => 'White House',
 )->geodetic(
     deg2rad(38.8987),  # latitude
     deg2rad(-77.0377), # longitude
     17 / 1000);	# height above sea level, Km
 
 foreach my $body ( $sun, $moon ) {
     my $fmt = Astro::App::Satpass2::FormatValue->new(
	 data => {
	     body => $body,
	     station => $station,
	     time => $time,
	 } );
     print join( ' ', $fmt->date(), $fmt->time(),
	 $fmt->name( width => 10 ),
	 $fmt->azimuth( bearing => 2 ),
	 $fmt->elevation() ), "\n";
 }

NOTICE

This is alpha code. It has been tested on my box, but has limited exposure to the wild. Also, the public interface may not be completely stable, and may change if needed to support Astro::App::Satpass2. I will try to document any incompatible changes.

DETAILS

This class is intended to take care of the details of performing field formatting for an Astro::App::Satpass2::Format object, and was actually written to format data for Template-Toolkit. It is not intended to be used outside one of these, though I suppose it could be.

This class is intended to be initialized with a hash containing data in known locations. Not coincidentally, the hash corresponds to the hashes produced by methods of interest in Astro::Coord::ECI and its subclasses.

METHODS

This class supports the following public methods.

Instantiator

new

$fmt = Astro::App::Satpass2::FormatValue->new();

This static method instantiates a new value formatter. It takes as arguments name/value pairs.

Because this class has no mutators you must give it all the information it needs to do its job when you instantiate it.

The following argument names are recognized:

data

This argument is a hash containing the data to be displayed. The keys in the hash are accessed by the various transformation and formatter methods. This argument is technically optional, but unless you have specified title => 1 (which see) you will not get a very useful object if you omit it.

If this hash contains a {time} key, the Astro::Coord::ECI objects in the {body} and {station} keys (if any) will be set to that value.

date_format

This argument is the string that the time_formatter will use to format dates. It is assumed that this format will not produce any time information, though this is not enforced. The default is whatever the default date format is for the time_formatter.

default

This optional argument is a hash used to override the defaults for the various formatters. The keys are formatter names, and the values of those keys are hashes containing the specific argument defaults.

desired_equinox_dynamical

This optional argument is the desired equinox in dynamical time. If specified as a non-zero Perl time, inertial coordinates will be precessed to this equinox. The default is 0.

fixed_width

This optional argument specifies whether or not fixed-width fields are to be produced. If true (the default) numeric default widths are applied where needed. If false the default width is '', which is the convention for variable-width fields.

local_coordinates

This optional argument provides the implementation of the local_coord() formatter method. You can provide either a code reference of one of the following strings:

az_rng --------- Azimuth and range;
azel ----------- Elevation and azimuth;
azel_rng ------- Elevation, azimuth and range;
equatorial ----- Right ascension and declination;
equatorial_rng - Right ascension, declination, and range.

The code reference will be called with the same arguments as were used for local_coord(), including the invocant.

The default is azel_rng.

overflow

If this optional argument is true (in the Perl sense, i.e. anything but undef, 0, or '') fields will be allowed to overflow their widths. If false (the default) too-long strings will be truncated on the right, and too-long numeric fields will generally be *-filled.

time_format

This argument is the string that the time_formatter will use to format times of day. It is assumed that this format will not produce any date information, though this is not enforced. The default is whatever the default time format is for the time_formatter.

time_formatter

This argument is either the name or an instance of an Astro::App::Satpass2::FormatTime subclass. This object is used to format times. The default is Astro::App::Satpass2::FormatTime.

title

If this argument is true, the formatter methods will produce titles rather than values. In this case the data hash is unused. The default is false.

title_gravity

This argument specifies the value for the title_gravity attribute. See the title_gravity() documentation for full details.

warner

This optional argument must be an instance of Astro::App::Satpass2::Warner. If not provided, a new Warner object will be instantiated.

Accessors

These are kept to a minimum, since the main purpose of the object is to provide formatting.

body

$fmt->body();

This accessor returns the contents of the {body} key of the original hash passed to the data argument when the object was instantiated. It returns a false value if the {body} key exists but is not an Astro::Coord::ECI|Astro::Coord::ECI, or if the key does not exist.

This accessor exists because the Astro::App::Satpass2::Format::Template list() method needs to look at the body to decide what to display.

Mutators

These also are kept to a minimum.

If called without an argument, all mutators act as accessors, and return the value of the attribute.

If called with an argument, they change the attribute (or croak if the new value is invalid), and return their invocant.

fixed_width

$fmt->fixed_width( 0 );
say 'Fixed-width formatting is ',
   $fmt->fixed_width() ? 'on' : 'off';

If false, this boolean attribute causes all widths not explicitly specified to default to '', which is the convention for non-fixed-width fields. It can also be set via the fixed_width argument to new(). The default is 1 (i.e. true).

If called without an argument, this method acts as an accessor, returning the current value.

This boolean attribute has a mutator because Template-Toolkit needs to modify it, and Template-Toolkit-style named arguments can't be used for clone() because of the way the interface is designed.

title_gravity

$fmt->title_gravity( 'bottom' );
say 'Title gravity is ', $fmt->title_gravity();

This attribute specifies how multiline titles are aligned. The possible values are 'top' or 'bottom'. The manifest constants TITLE_GRAVITY_TOP and TITLE_GRAVITY_BOTTOM are defined to represent these, but they are not exported.

If you specify 'bottom', you get an extra empty line above the titles. This is an annoying behavior necessitated by the fact that the first line of the first title has to be inserted into the output before we know how many lines are needed to print all the titles. So we force an extra line with blanks to get the process rolling.

This hack means that you do not want to use 'bottom' unless you intend to actually display all the lines of each title.

The default is 'top'.

This attribute has a mutator because Template-Toolkit needs to modify it.

Transformations

Some of the methods of interest produce hashes that contain supplementary data. For example, the output of the Astro::Coord::ECI::TLE pass() method may contain an <{appulse}> key describing the appulsed body. These methods give access to such data. If the requested data exists, they typically return an Astro::App::Satpass2::FormatValue object, though they may return a reference to an array of them, or to an iterator function. If the requested data do not exist, they typically return undef.

appulse

my $apls = $fmt->appulse();

This method returns an Astro::App::Satpass2::FormatValue object based on the invocant, with the data coming from the {appulse} key of the original object's data, augmented with the {station} and {time} of the original data.

bodies

my $array_ref = $fmt->bodies();

For reasons that seemed logical at the time, the Astro::App::Satpass2 position() method produces a hash containing the time, some other relevant data, and a {bodies} key which contains a reference to an array of all the relevant bodies.

This method extracts an array of more-normally-structured Astro::App::Satpass2::FormatValue objects which give access to the original bodies.

center

$center = $fmt->center();

This method returns an Astro::App::Satpass2::FormatValue object based on the invocant, with the data coming from the {center} key of the original object's data, augmented with the {station} and {time} of the original data.

clone

my $clone = $fmt->( %arg );

This method performs a shallow clone the invocant. That is to say, the clone is a separate object, but it shares all contained objects and references with the original object. If any arguments are passed, they are used to initialize the cloned object, instead of the corresponding data from the invocant.

earth

my $earth = $fmt->earth();

This method returns an Astro::App::Satpass2::FormatValue object based on the invocant, with its {station} key set to the center of the Earth.

events

foreach my $event ( @{ $fmt->events() || [] } ) {
    ... do something with the event ...
}

This method returns a reference to an array of Astro::App::Satpass2::FormatValue objects manufactured out of the contents of the {events} key of the invocant's data.

reflections

$array_ref = $fmt->reflections();

This method returns a reference to an array of Astro::App::Satpass2::FormatValue objects which represent the results of calling $fmt->body()->reflection(), passing it the contents of the {station} and {time} keys. It will return undef if the body does not support this method, or if it is below the horizon or not lit.

station

my $station = $fmt->station();

This method returns an object identical to the invocant, with the exception that the {body} and {station} contents are exchanged. With this,

$fmt->station()->latitude()

(e.g.) gets you the latitude of the observing station, whereas

$fmt->latitude()

would get you the latitude of the orbiting body.

Formatters

Each formatter converts the value of a specific key or keys in the data hash to text. Typically the conversion is to a fixed-width field unless the width argument is non-numeric. If the underlying item does not exist, a user-specified string will be returned instead, or spaces if no string was specified.

All the formatter arguments are passed by name: that is, as name/value pairs. Because of the idiosyncrasies of Template-Toolkit, or because of the author's lack of experience with it, some weirdness has been introduced into what would have been a straightforward signature:

* Template-Toolkit recognizes special named-argument syntax, and presents the arguments as a hash appended to the argument list. Therefore, if the formatters see a hash as the last argument, that hash will be expanded into a list and prepended to the argument list. Because Template-Toolkit does not supply an empty hash if none of its named arguments are seen, you can not pass a hash as the last argument.

* Template-Toolkit seems to have a strong preference for dealing with arrays as references. But array references are not flattened when passed as arguments. If the caller wants an array reference flattened, it must be made into an instance of Astro::App::Satpass2::Wrap::Array. This is really (I think and hope!) only a problem for whoever writes the code reference that gets passed to the local_coordinates argument of new() (i.e. me).

The summary of all this is that arguments are taken in the following order:

1) arguments from the final hash, if any
2) everything else except
3) Astro::App::Satpass2::Wrap::Array objects, which are expanded and put last.

Since arguments are passed by name, you can specify the same argument more than once. If this happens, the last specification of the argument is the one taken.

One additional complication: for convenience in overriding default titles, if the list of arguments from item (2) above ('everything else') has an odd number of elements, 'title' is prepended. The net result of this is that if $title is an Astro::App::Satpass2::FormatValue object with title => 1, something like $title->azimuth( '' ) will produce an empty field of the proper width.

The following arguments are accepted by all formatters:

align_left: This argument specifies that the given value be left-aligned in its field. This defaults to true for text items, and false for numeric items.
literal: This argument specifies text to be displayed in place of the underlying datum.
missing: This argument specifies the text to be filled in if the underlying datum is not available. It defaults to spaces.
title: This argument specifies the text to be used as the title of the formatter -- that is, the text which is displayed when the formatter is initialized with title => 1. The default is appropriate to the formatter.

almanac

print $fmt->almanac();

The almanac_hash() method provided by some subclasses of Astro::Coord::ECI returns a hash which includes an {almanac} key, which contains various items describing the almanac entry. This method provides access to the contents of the {almanac} key.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any almanac_pseudo_units units are accepted; anything else will result in an exception. The default is description.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 40.

altitude

print $fmt->altitude();

This method formats the altitude of the {body} object above sea level.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 1.
units: This argument specifies the units of the field. Any length units are accepted; anything else will result in an exception. The default is kilometers.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 7.

angle

print $fmt->angle();

This method formats the {angle} value, which typically represents an appulse angle.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 1.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 5.

apoapsis

print $fmt->apoapsis();

This method formats the apoapsis of the {body} object's orbit.

In addition to the standard arguments, it takes the following:

as_altitude: If this boolean argument is true (in the Perl sense) the value is given as altitude above the Earth's surface. If false, the value is given as distance from the Earth's center. The default is 1.
places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 0.
units: This argument specifies the units of the field. Any length units are accepted; anything else will result in an exception. The default is kilometers.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 6.

apogee

print $fmt->apogee();

This method formats the apogee of the {body} object's orbit. Yes, this is the same as the apoapsis.

In addition to the standard arguments, it takes the following:

as_altitude: If this boolean argument is true (in the Perl sense) the value is given as altitude above the Earth's surface. If false, the value is given as distance from the Earth's center. The default is 1.
places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 0.
units: This argument specifies the units of the field. Any length units are accepted; anything else will result in an exception. The default is kilometers.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 6.

argument_of_perigee

print $fmt->argument_of_perigee();

This method formats the argument of perigee from the {body} object's TLE data.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 4.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 9.

ascending_node

print $fmt->ascending_node();

This method formats the ascending node from the {body} object's TLE data.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 2.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is right_ascension.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 11.

azimuth

print $fmt->azimuth();

This method formats the azimuth of the {body} object as seen from the {station} object.

In addition to the standard arguments, it takes the following:

bearing: This argument specifies the size of the bearing information to append to the azimuth. If zero or any non-numeric value, no bearing information will be appended. The default is 0.
places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 1.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 5.

b_star_drag

print $fmt->b_star_drag();

This method formats the B* drag from the {body} object's TLE data..

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 4.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 11.

classification

print $fmt->classification();

This method formats the classification of the {body} object's TLE data. This will usually be 'U', for 'unclassified'.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any string_pseudo_units units are accepted; anything else will result in an exception. The default is string.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 1.

date

print $fmt->date();

This method formats the {time} value using the date_format template. This is intended to produce the date, without time information.

In addition to the standard arguments, it takes the following:

delta: This argument specifies a number of seconds to add to the value before it is formatted. The default is 0.
format: This argument specifies the format to use for formatting the value. The default is ...
gmt: If this boolean argument is true, the value is formatted in GMT, regardless of how the time formatter is set up. If false, it is formatted according to the time_formatter's zone setting. The default is the time_formatter's gmt setting.
places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 5.
units: This argument specifies the units of the field. Any time_units units are accepted; anything else will result in an exception. The default is local.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is .

declination

print $fmt->declination();

This method formats the declination of the {body} object as seen from the {station} object.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 1.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 5.

eccentricity

print $fmt->eccentricity();

This method formats the eccentricity of the {body} object's orbit.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 5.
units: This argument specifies the units of the field. Any dimensionless units are accepted; anything else will result in an exception. The default is unity.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 8.

effective_date

print $fmt->effective_date();

This method formats the effective date of the {body} object's TLE data.

In addition to the standard arguments, it takes the following:

format: This argument specifies the format to use for formatting the value. The default is ...
gmt: If this boolean argument is true, the value is formatted in GMT, regardless of how the time formatter is set up. If false, it is formatted according to the time_formatter's zone setting. The default is the time_formatter's gmt setting.
places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is .
units: This argument specifies the units of the field. Any time_units units are accepted; anything else will result in an exception. The default is local.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is .

element_number

print $fmt->element_number();

This method formats the number of the {body} object's TLE data. This is usually incremented each time a new set is published.

In addition to the standard arguments, it takes the following:

width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 4.

elevation

print $fmt->elevation();

This method formats the elevation of the {body} object above the horizon as seen from the {station} object.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 1.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 5.

ephemeris_type

print $fmt->ephemeris_type();

This method formats the ephemeris type of the {body} object's TLE data. This is supposed to say which model is to be used to calculate the object's position, but in practice is typically 0 or blank.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any string_pseudo_units units are accepted; anything else will result in an exception. The default is string.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 1.

epoch

print $fmt->epoch();

This method formats the epoch from the {body} object's TLE data.

In addition to the standard arguments, it takes the following:

format: This argument specifies the format to use for formatting the value. The default is ...
gmt: If this boolean argument is true, the value is formatted in GMT, regardless of how the time formatter is set up. If false, it is formatted according to the time_formatter's zone setting. The default is the time_formatter's gmt setting.
places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is .
units: This argument specifies the units of the field. Any time_units units are accepted; anything else will result in an exception. The default is local.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is .

event

print $fmt->event();

This method formats the contents of {event}, which generally comes from an Astro::Coord::ECI::TLE pass() calculation.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any event_pseudo_units units are accepted; anything else will result in an exception. The default is localized.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 5.

first_derivative

print $fmt->first_derivative();

This method formats the first derivative from the {body} object's TLE data. The units are actually angle per minute squared, but this formatter treats them as angle. That is, it will give you output in radians per minute squared if you so desire, but not in radians per second squared.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 10.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 17.

fraction_lit

print $fmt->fraction_lit();

This method formats the fraction of the {body} object which is lit. This is only available if that object supports the phase() method.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 2.
units: This argument specifies the units of the field. Any dimensionless units are accepted; anything else will result in an exception. The default is unity.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 4.

illumination

print $fmt->illumination();

This method formats the contents of {illumination}, which generally comes from an Astro::Coord::ECI::TLE pass() calculation.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any event_pseudo_units units are accepted; anything else will result in an exception. The default is localized.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 5.

inclination

print $fmt->inclination();

This method formats the orbital inclination from the {body} object's TLE data.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 4.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 8.

inertial

print $fmt->inertial()

This method formats the inertial attribute of the {body} object, as 0 if the attribute is false, or 1 if it is true.

In addition to the standard arguments, it takes the following:

width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 1.

international

print $fmt->international();

This method formats the international launch designator from the {body} object's TLE data.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any string_pseudo_units units are accepted; anything else will result in an exception. The default is string.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 8.

latitude

print $fmt->latitude();

This method formats the latitude of the {body} object.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 4.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 8.

local_coord

print $fmt->local_coord();

This method formats the local coordinates as specified by the local_coordinates argument when the object was initialized. It has no arguments of its own, but will pass through any arguments given to the methods it calls. You can pass arguments selectively by specifying them as a hash - for example $fmt->local_coord( title => { azimuth => 'azimuth', elevation => 'elevation', }, );

Scalar arguments will be passed to all called methods, except for append, which will be appended to the entire formatted value.

longitude

print $fmt->longitude();

This method formats the longitude of the {body} object.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 4.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 9.

magnitude

print $fmt->magnitude();

This method formats the contents of {magnitude}, which generally represent the magnitude of an Iridium flare.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 1.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 4.

maidenhead

print $fmt->maidenhead();

This method formats the Maidenhead Grid Locator position of the {body} object.

In addition to the standard arguments, it takes the following:

places: This argument specifies the precision of the position, as the number of grid levels to provide. The default is half the width, truncated to an integer. If no specific width is provided, the default is 3.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 6.

mean_anomaly

print $fmt->mean_anomaly();

This method formats the mean anomaly from the {body} object's TLE data.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 4.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 9.

mean_motion

print $fmt->mean_motion();

This method formats the mean motion from the {body} object's TLE data. The units are actually angle per minute, but this formatter treats them as angle. That is, it will give you output in radians per minute if you so desire, but not in radians per second.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 10.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 12.

mma

print $fmt->mma();

This method formats the contents of {mma}, which generally indicates the flaring antenna for an Iridium flare.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any string_pseudo_units units are accepted; anything else will result in an exception. The default is string.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 3.

name

print $fmt->name();

This method formats the name of the {body} object. If the name is missing and you specify missing => 'oid' the OID will be displayed instead.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any string_pseudo_units units are accepted; anything else will result in an exception. The default is string.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 24.

oid

print $fmt->oid();

This method formats the OID of the {body} object.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any string_pseudo_units units are accepted; anything else will result in an exception. The default is string.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 6.

operational

print $fmt->operational();

This method formats the operational status of the {body} object. This is generally only available if the object represents an Iridium satellite.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any string_pseudo_units units are accepted; anything else will result in an exception. The default is string.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 1.

periapsis

print $fmt->periapsis();

This method formats the periapsis of the {body} object's orbit.

In addition to the standard arguments, it takes the following:

as_altitude: If this boolean argument is true (in the Perl sense) the value is given as altitude above the Earth's surface. If false, the value is given as distance from the Earth's center. The default is 1.
places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 0.
units: This argument specifies the units of the field. Any length units are accepted; anything else will result in an exception. The default is kilometers.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 6.

perigee

print $fmt->perigee();

This method formats the perigee of the {body} object's orbit. Yes, this is the same as the periapsis.

In addition to the standard arguments, it takes the following:

as_altitude: If this boolean argument is true (in the Perl sense) the value is given as altitude above the Earth's surface. If false, the value is given as distance from the Earth's center. The default is 1.
places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 0.
units: This argument specifies the units of the field. Any length units are accepted; anything else will result in an exception. The default is kilometers.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 6.

period

print $fmt->period();

This method formats the period of the {body} object's orbit.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 0.
units: This argument specifies the units of the field. Any duration units are accepted; anything else will result in an exception. The default is composite.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 12.

phase

print $fmt->phase();

This method formats the phase of the {body} object. This is only available if that object supports the phase() method.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 0.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 4.

range

print $fmt->range();

This method formats the distance of the {body} object from the {station} object.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 1.
units: This argument specifies the units of the field. Any length units are accepted; anything else will result in an exception. The default is kilometers.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 10.

revolutions_at_epoch

print $fmt->revolutions_at_epoch();

This method formats the revolutions at epoch from the {body} object's TLE data.

In addition to the standard arguments, it takes the following:

width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 6.

right_ascension

print $fmt->right_ascension();

This method formats the right ascension of the {body} object as seen from the {station} object.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 0.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is right_ascension.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 8.

second_derivative

print $fmt->second_derivative();

This method formats the second derivative from the {body} object's TLE data. The units are actually angle per minute cubed, but this formatter treats them as angle. That is, it will give you output in radians per minute cubed if you so desire, but not in radians per second cubed.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 10.
units: This argument specifies the units of the field. Any angle_units units are accepted; anything else will result in an exception. The default is degrees.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 17.

semimajor

print $fmt->semimajor();

This method formats the semimajor axis of the {body} object's orbit, calculated using that object's semimajor() method.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 0.
units: This argument specifies the units of the field. Any length units are accepted; anything else will result in an exception. The default is kilometers.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 6.

semiminor

print $fmt->semiminor();

This method formats the semiminor axis of the {body} object's orbit, calculated using that object's semiminor() method.

In addition to the standard arguments, it takes the following:

places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 0.
units: This argument specifies the units of the field. Any length units are accepted; anything else will result in an exception. The default is kilometers.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 6.

status

print $fmt->status();

This method formats the contents of {status}, which usually come from the Astro::App::Satpass2 position() method.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any string_pseudo_units units are accepted; anything else will result in an exception. The default is string.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 60.

time

print $fmt->time();

This method formats the {time} value using the time_format template. This is intended to produce the time, without date information.

In addition to the standard arguments, it takes the following:

delta: This argument specifies a number of seconds to add to the value before it is formatted. The default is 0.
format: This argument specifies the format to use for formatting the value. The default is ...
gmt: If this boolean argument is true, the value is formatted in GMT, regardless of how the time formatter is set up. If false, it is formatted according to the time_formatter's zone setting. The default is the time_formatter's gmt setting.
places: This argument specifies the number of decimal places in the field. Specify a non-numeric value if you do not wish to enforce a specific number of decimal places. The default is 5.
units: This argument specifies the units of the field. Any time_units units are accepted; anything else will result in an exception. The default is local.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is .

tle

print $fmt->tle();

This method formats the TLE data from the {body} object. Unlike the other formatters, which produce a fixed-width string, this formatter produces a block of text, whatever is contained by the {body} object's tle attribute if any.

type

print $fmt->type();

This method formats the contents of {type}. This usually comes from the flare() method, and says whether the flare occurred in the am, day, or pm.

In addition to the standard arguments, it takes the following:

units: This argument specifies the units of the field. Any string_pseudo_units units are accepted; anything else will result in an exception. The default is string.
width: This argument specifies the width of the field. Specify a non-numeric value if you do not wish to enforce a specific width. The default is 3.

Title Control

Titles can consist of multiple lines, wrapped with Text::Wrap. The display is 'top-heavy', meaning that the column titles are justified to the top.

Nothing special needs to be done to get the first line, other than to initialize the object title => 1. To get all the lines, you need to use a while loop, calling more_title_lines() in the test. When this returns false you must exit the loop, otherwise you loop infinitely.

is_valid_title_gravity

Returns a true value if the argument is a valid title gravity setting, and a false value otherwise. Can be called as a static method, or even a subroutine, though it is not exported.

more_title_lines

my $fmt = Astro::App::Satpass2::Format->new( title => 1 );
while ( $fmt->more_title_lines() ) {
    print join( ' ',
        $fmt->azimuth( title => 'Azimuth of object',
            bearing => 2 ),
        $fmt->elevation( title => 'Elevation of object' ),
    ), "\n";
}

This method returns true until there are no more lines of title to display. It also increments the internal line counter causing the next line of title to be displayed.

reset_title_lines

my $fmt->reset_title_lines();

This method resets the title line logic to its original state. You will not normally need to call this unless you want to display titles more than once and you have previously exited a more_title_lines() loop prematurely.

UNITS

Most of the format effectors format a quantity that is measured in some physical units; that is, kilometers, feet, seconds, or whatever. The units= argument can be used to specify the displayed units for the field. This mechanism has been subverted in a couple cases to select among the representations of items that have more than one representation, even when the different representations are not, strictly speaking, physical units.

Each format effector that has physical units has an associated dimension, which determines which units are valid for it. The dimension specifies units, synonyms for canonical units, and the default units, though the individual format effector can have its own default (e.g. right_ascension).

Typically the default field widths and decimal places are appropriate for the default units, so if you specify different units you should probably specify the field width and decimal places as well.

The dimensions are:

almanac_pseudo_units

The first example is a case where the units mechanism was subverted to select among alternate representations, rather than to convert between physical units. The possible pseudo-units are:

description = the text description of the event;

event = the generic name of the event (e.g. 'horizon' for rise or set);

detail = the numeric event detail, whose meaning depends on the event (e.g. for 'horizon', 1 is rise and 0 is set).

The default is 'description'.

angle_units

This dimension represents a geometric angle. The possible units are:

bearing = a compass bearing;

decimal = a synonym for degrees;

degrees = angle in decimal degrees;

radians = angle in radians;

phase = name of phase ('new', 'waxing crescent', and so on);

right_ascension = angle in hours, minutes, and seconds of right ascension.

When the angle units are specified as units => 'bearing', the precision of the bearing is specified by the bearing argument. That is, bearing => 1 gets you the cardinal points (N, E, S and W), bearing => 2 gets you the semi-cardinal points, and similarly for bearing => 3. If bearing is not specified it defaults to the same value as the width argument, or 2 if no width is specified. The net result is that you need to specify the bearing argument if you specify width => '' and do not like the default of 2. Yes, I could have equivocated on places, but this seemed more straight forward.

The default is normally degrees, though this is overridden for right_ascension.

dimensionless

A few displayed quantities are simply numbers, having no associated physical dimension. These can be specified as:

percent = display as a percentage value, without the trailing '%';

unity = display unaltered.

The default is unity.

duration

This dimension represents a span of time, such as an orbital period. The units are:

composite = days hours:minutes:seconds.fraction;

days = duration in days and fractions of days;

hours = duration in hours and fractions of hours;

minutes = duration in minutes and fractions of minutes;

seconds = duration in seconds and fractions of seconds.

The default is composite.

event_pseudo_units

Like almanac_pseudo_units, this is not a physical dimension, just a way of selecting different representations. The units are:

integer = event number (see Astro::Coord::ECI::TLE);

localized = localized event name;

string = unlocalized event name.

The default is localized.

length

This dimension represents lengths and distances. The possible units are:

feet = US/British feet;

ft = synonym for 'feet';

kilometers = standard kilometers;

km = synonym for kilometers;

meters = standard meters;

m = synonym for 'meters';

miles = statute miles.

The default is kilometers.

string_pseudo_units

Like almanac_pseudo_units, this is not a physical dimension, just a way of selecting different representations. The units are:

lower_case = all lower case;

string = the unmodified string;

title_case = lower case, with initial letters upper case,

upper_case = all upper case.

time_units

This dimension represents time. The possible units are:

days_since_epoch = the number of days and fractions thereof since the epoch of the body (undefined if there is no epoch);

gmt = GMT;

julian = Julian day (implies GMT -- you may want to set the places argument for this);

local = local time (actually, whatever zone the time formatter is set to);

universal = an alias for gmt;

z = an alias for gmt;

zulu = an alias for gmt.

The default is local.

SUPPORT

Support is by the author. Please file bug reports at http://rt.cpan.org, or in electronic mail to the author.

AUTHOR

Thomas R. Wyant, III wyant at cpan dot org

COPYRIGHT AND LICENSE

This program is free software; you can redistribute it and/or modify it under the same terms as Perl 5.10.0. For more details, see the full text of the licenses in the directory LICENSES.

This program is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose.

To install Astro::App::Satpass2, copy and paste the appropriate command in to your terminal.

cpanm

cpanm Astro::App::Satpass2

CPAN shell

perl -MCPAN -e shell
install Astro::App::Satpass2

For more information on module installation, please visit the detailed CPAN module installation guide.

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