NAME
Geo::GML - Geography Markup Language processing
INHERITANCE
Geo::GML has extra code in
Geo::GML::GeoPoint
Geo::GML
is a XML::Compile::Cache
is a XML::Compile::Schema
is a XML::CompileSYNOPSIS
use Geo::GML ':gml321';
my $gml = Geo::GML->new('READER', version => '3.2.1');
# see XML::Compile::Cache on how to use readers and writers
my $data = $gml->reader("gml:GridCoverage")->($xmlmsg);
my $xml = $gml->writer($sometype)->($doc, $perldata);
# or without help of the cache, XML::Compile::Schema
my $r = $gml->compile(READER => $sometype);
my $data = $r->($xml);
# super simple
my ($type, $data) = Geo::GML->from('data.xml');
# overview (large) on all defined elements
$gml->printIndex;
# To discover the perl datastructures to be passed
print $gml->template("gml:Surface");
# autoloaded logic to convert Geo::Point into GML
$data->{...somewhere...} = $gml->GPtoGML($objects);DESCRIPTION
Provides access to the GML definitions specified in XML. The details about GML structures can differ, and therefore you should be explicit which versions you understand and produce.
If you need the <b>most recent</b> version of GML, then you get involved with the ISO19139 standard. See CPAN module Geo::ISO19139.
The first releases of this module will not powerful, but hopefully people contribute. For instance, an example conversion script between various versions is very welcome! It would be nice to help each other. I will clean-up the implementation, to make it publishable, but do not have the knowledge about what is needed.
METHODS
Constructors
Geo::GML->from(XMLDATA, OPTIONS)
Read a EOP structure from a data source, which can be anything acceptable by dataToXML(): a XML::LibXML::Element, XML as string or ref-string, filename, filehandle or known namespace.
Returned is the product (the type of the root node) and the parsed data-structure. The EOP version used for decoding is autodetected, unless specified.
See examples/read_gml.pl
example:
my ($type, $data) = Geo::GML->from('data.xml');Geo::GML->new('READER'|'WRITER'|'RW', OPTIONS)
Option --Defined in --Default
allow_undeclared <true>
any_element XML::Compile::Cache ATTEMPT
hook XML::Compile::Schema undef
hooks XML::Compile::Schema []
ignore_unused_tags XML::Compile::Schema <false>
key_rewrite XML::Compile::Schema []
opts_readers XML::Compile::Cache []
opts_rw XML::Compile::Cache <some>
opts_writers XML::Compile::Cache []
prefixes undef
schema_dirs XML::Compile undef
typemap XML::Compile::Schema {}
version <required>. allow_undeclared => BOOLEAN
In the optimal case, all types used in your application are declared during the initiation phase of your program. This will make it easy to write a fast daemon application, or transform your program into a daemon later. So: "false" would be a good setting. However, on the moment, the developer of this module has no idea which types people will use. Please help me with the specs!
All any elements will be ATTEMPTed to be processed at run-time by default.
The GML specification will require PREFIXED key rewrite, because the complexity of namespaces is enormous. Besides, mixed elements are processed as STRUCTURAL by default (mixed in texts ignored).
. any_element => CODE|'TAKE_ALL'|'SKIP_ALL'|'ATTEMPT'
. hook => ARRAY-WITH-HOOKDATA | HOOK
. hooks => ARRAY-OF-HOOK
. ignore_unused_tags => BOOLEAN|REGEXP
. key_rewrite => HASH|CODE|ARRAY-of-HASH-and-CODE
. opts_readers => HASH|ARRAY-of-PAIRS
. opts_rw => HASH|ARRAY-of-PAIRS
. opts_writers => HASH|ARRAY-of-PAIRS
. prefixes => ARRAY|HASH
Prefix abbreviations, to be used by cache object. Which prefixes are defined depends on the schema version.
. schema_dirs => DIRECTORY|ARRAY-OF-DIRECTORIES
. typemap => HASH
. version => VERSION|NAMESPACE
Only used when the object is created directly from this base-class. It determines which GML syntax is to be used. Can be a VERSION like "3.1.1" or a NAMESPACE URI like 'NS_GML_300'.
Accessors
$obj->addHook(HOOKDATA|HOOK|undef)
$obj->addHooks(HOOK, [HOOK, ...])
$obj->addKeyRewrite(PREDEF|CODE|HASH, ...)
$obj->addSchemaDirs(DIRECTORIES|FILENAME)
Geo::GML->addSchemaDirs(DIRECTORIES|FILENAME)
$obj->addSchemas(XML, OPTIONS)
$obj->addTypemap(PAIR)
$obj->addTypemaps(PAIRS)
$obj->allowUndeclared([BOOLEAN])
$obj->direction
Returns 'READER', 'WRITER', or 'RW'.
$obj->hooks
$obj->prefix(PREFIX)
$obj->prefixFor(URI)
$obj->prefixes([PAIRS|ARRAY|HASH])
$obj->useSchema(SCHEMA, [SCHEMA])
$obj->version
GML version, for instance '3.2.1'.
Compilers
$obj->compile(('READER'|'WRITER'), TYPE, OPTIONS)
$obj->compileAll(['READER'|'WRITER'|'RW', [NAMESPACE]])
Geo::GML->dataToXML(NODE|REF-XML-STRING|XML-STRING|FILENAME|FILEHANDLE|KNOWN)
$obj->reader(TYPE|NAME, OPTIONS)
$obj->template('PERL'|'XML', TYPE, OPTIONS)
See XML::Compile::Schema::template(). This will create an example of the data-structure based on GML. All OPTIONS are passed to the template generator, the only reason to have this method, is to avoid the need to collect all the GML XML files yourself.
Option --Defined in --Default
abstract_types XML::Compile::Schema 'IGNORE'
attributes_qualified XML::Compile::Schema <undef>
elements_qualified XML::Compile::Schema <undef>
include_namespaces XML::Compile::Schema <true>
indent XML::Compile::Schema " "
show_comments XML::Compile::Schema ALL. abstract_types => 'ERROR'|'IGNORE'|'ACCEPT'
. attributes_qualified => BOOLEAN
. elements_qualified => 'ALL'|'TOP'|'NONE'|BOOLEAN
. include_namespaces => BOOLEAN
. indent => STRING
. show_comments => STRING|'ALL'|'NONE'
example:
use Geo::GML;
use Geo::GML::Util qw/NS_GML_321/;
use XML::Compile::Util qw/pack_type/;
my $gml = Geo::GML->new(version => NS_GML_321);
# to simplify the output, reducing often available large blocks
my @types = qw/gml:MetaDataPropertyType gml:StringOrRefType
gml:ReferenceType/;
my %hook = (type => \@collapse_types, replace => 'COLLAPSE');
# generate the data-structure
my $type = 'gml:RectifiedGridCoverage'; # any element name
print $gml->template(PERL => $type, hook => \%hook);$obj->writer(TYPE|NAME)
Helpers
$obj->GPtoGML(OBJECT, OPTIONS)
Administration
$obj->declare('READER'|'WRITER'|'RW', TYPE|ARRAY-of-TYPES, OPTIONS)
$obj->elements
$obj->findName(NAME)
$obj->findSchemaFile(FILENAME)
Geo::GML->findSchemaFile(FILENAME)
$obj->importDefinitions(XMLDATA, OPTIONS)
$obj->knownNamespace(NAMESPACE|PAIRS)
Geo::GML->knownNamespace(NAMESPACE|PAIRS)
$obj->namespaces
$obj->printIndex([FILEHANDLE], OPTIONS)
List all the elements which can be produced with the schema. By default, this only shows the elements and excludes the abstract elements from the list. The selected FILEHANDLE is the default to print to.
Option --Defined in --Default
show_declared XML::Compile::Cache <true>. show_declared => BOOLEAN
$obj->types
$obj->walkTree(NODE, CODE)
DETAILS
DIAGNOSTICS
Error: cannot find pre-installed name-space files
Use $ENV{SCHEMA_LOCATION} or new(schema_dirs) to express location of installed name-space files, which came with the XML::Compile distribution package.
Error: don't known how to interpret XML data
SEE ALSO
This module is part of Geo-GML distribution version 0.15, built on March 19, 2009. Website: http://perl.overmeer.net/geo/ All modules in this suite: "Geo::GML", "Geo::ISO19139", "Geo::EOP", "Geo::Point", "Geo::Proj4", "Geo::WKT", and "Math::Polygon".
Please post questions or ideas to http://geo-perl@list.hut.fi|the Geo-Perl mailinglist
COPYRIGHTS
License of the CODE
Copyrights of the perl code and the related documentation by 2008-2009 by Mark Overmeer. For other contributors see ChangeLog.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See http://www.perl.com/perl/misc/Artistic.html
License of the SCHEMAS
The included schemas are copyrighted by the Open Geospatial Consortium, Inc. They are unmodified copied from the files at http://schemas.opengis.net. Read OGCs disclaimer and copyright statements on documentation and software at http://www.opengeospatial.org/ogc/legal. The license text is also included in this CPAN distribution.