Brian M. Ames
and 1 contributors


Rinchi::CIGIPP::EarthReferenceModelDefinition - Perl extension for the Common Image Generator Interface - Earth Reference Model Definition data packet. data packet. =head1 SYNOPSIS

  use Rinchi::CIGIPP::EarthReferenceModelDefinition;
  my $erm_def = Rinchi::CIGIPP::EarthReferenceModelDefinition->new();

  $packet_type = $erm_def->packet_type();
  $packet_size = $erm_def->packet_size();
  $custom_erm = $erm_def->custom_erm(Rinchi::CIGIPP->Enable);
  $equatorial_radius = $erm_def->equatorial_radius(6.458);
  $flattening = $erm_def->flattening(32.413);


The default Earth Reference Model (ERM) used for geodetic positioning is WGS 84. The Host may define another ERM by sending an Earth Reference Model Definition packet to the IG. This packet defines the equatorial radius and the flattening of the new reference ellipsoid.

When the IG receives an Earth Reference Model Definition packet, it should set the Earth Reference Model attribute of the Start of Frame packet to Host-Defined (1). If, for some reason, the IG cannot support the ERM defined by the Host, the attribute should be set to WGS 84 (0).


None by default.


new $erm_def = Rinchi::CIGIPP::EarthReferenceModelDefinition->new()

Constructor for Rinchi::EarthReferenceModelDefinition.

sub packet_type()
 $value = $erm_def->packet_type();

Data Packet Identifier.

This attribute identifies this data packet as the Earth Reference Model Definition packet. The value of this attribute must be 19.

sub packet_size()
 $value = $erm_def->packet_size();

Data Packet Size.

This attribute indicates the number of bytes in this data packet. The value of this attribute must be 24.

sub custom_erm([$newValue])
 $value = $erm_def->custom_erm($newValue);

Custom ERM Enable.

This attribute specifies whether the IG should use the Earth Reference Model (ERM) defined by this packet.

If this attribute is set to Disable (0), the IG will use the WGS 84 reference model and all other attributes in this packet will be ignored.

    Disable   0
    Enable    1
sub equatorial_radius([$newValue])
 $value = $erm_def->equatorial_radius($newValue);

Equatorial Radius.

This attribute specifies the semi-major axis of the ellipsoid.

sub flattening([$newValue])
 $value = $erm_def->flattening($newValue);


This attribute specifies the flattening of the ellipsoid.

sub pack()
 $value = $erm_def->pack();

Returns the packed data packet.

sub unpack()
 $value = $erm_def->unpack();

Unpacks the packed data packet.

sub byte_swap()

Byte swaps the packed data packet.


Refer the the Common Image Generator Interface ICD which may be had at this URL:


Brian M. Ames, <>


Copyright (C) 2009 by Brian M. Ames

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.6 or, at your option, any later version of Perl 5 you may have available.

2 POD Errors

The following errors were encountered while parsing the POD:

Around line 73:

'=item' outside of any '=over'

Around line 306:

You forgot a '=back' before '=head1'