Geo::GDAL Class Reference

GDAL utility functions and a root class for raster classes. More...

Inheritance diagram for Geo::GDAL:

Classes
class	AsyncReader
	Enable asynchronous requests. More...
class	Band
	A raster band. More...
class	ColorTable
	A color table in a raster band. More...
class	Dataset
	A set of associated raster bands. More...
class	Driver
	A raster format driver. More...
class	GCP
	A ground control point for georeferencing images. More...
class	GeoTransform
	An array of affine transformation coefficients. More...
class	MajorObject
	An object, which holds meta data. More...
class	RasterAttributeTable
	An attribute table in a raster band. More...
class	Transformer
	This class is not yet documented for the GDAL Perl bindings. More...
class	VSIF
	A GDAL virtual file system. More...

Public Member Functions
public list	AccessTypes ()
public Geo::GDAL::Dataset	AutoCreateWarpedVRT (Geo::GDAL::Dataset src, Geo::OSR::SpatialReference src_srs=undef, Geo::OSR::SpatialReference dst_srs=undef, scalar ResampleAlg='NearestNeighbour', scalar maxerror=0.0)
public method	CPLBinaryToHex ()
public method	CPLHexToBinary ()
public list	Child (scalar node, scalar i)
public list	Children (scalar node)
public method	ComputeMedianCutPCT (Geo::GDAL::Band red, Geo::GDAL::Band green, Geo::GDAL::Band blue, scalar num_colors, scalar colors, subref progress, scalar progress_data)
public method	ComputeProximity (Geo::GDAL::Band src, Geo::GDAL::Band proximity, hashref options, subref progress, scalar progress_data)
public scalar	DataTypeIsComplex (scalar DataType)
public list	DataTypeValueRange (scalar DataType)
public list	DataTypes ()
public method	Debug ()
public scalar	DecToDMS (scalar angle, scalar axis, scalar precision=2)
public scalar	DecToPackedDMS (scalar dec)
public method	DitherRGB2PCT (scalar red, scalar green, scalar blue, scalar target, scalar colors, subref progress, scalar progress_data)
public method	EscapeString ()
public scalar	FindFile (scalar class, scalar basename)
public method	FinderClean ()
public method	GOA2GetAccessToken ()
public method	GOA2GetAuthorizationURL ()
public method	GOA2GetRefreshToken ()
public scalar	GetCacheMax ()
public scalar	GetCacheUsed ()
public scalar	GetConfigOption (scalar key, scalar default)
public scalar	GetDataTypeSize (scalar DataType)
public Geo::GDAL::Driver	GetDriver (scalar name)
public list	GetDriverNames ()
public method	GetJPEG2000StructureAsString ()
public Geo::GDAL::Driver	IdentifyDriver (scalar path, scalar siblings)
public list	NodeData (scalar node)
public scalar	NodeType (scalar type)
public list	NodeTypes ()
public Geo::GDAL::Dataset	Open (scalar name, scalar access= 'ReadOnly')
public Geo::GDAL::Dataset	OpenEx (scalar name, scalar open_flags=0, array reference allowed_drivers=undef, array reference open_options=undef, array reference sibling_files=undef)
public Geo::GDAL::Dataset	OpenShared (scalar name, scalar access= 'ReadOnly')
public scalar	PackCharacter (scalar DataType)
public scalar	PackedDMSToDec (scalar packed)
public array reference	ParseXMLString (scalar XML)
public method	Polygonize (Geo::GDAL::Band src, Geo::GDAL::Band mask, Geo::OGR::Layer out, scalar PixValField, hashref options, subref progress, scalar progress_data)
public method	PopFinderLocation ()
public method	PushFinderLocation (scalar path)
public list	RIOResamplingTypes ()
public method	RasterizeLayer (Geo::GDAL::Dataset ds, arrayref bands, Geo::OGR::Layer layer, scalar transformer, scalar arg, arrayref burn_values, hashref options, subref progress, scalar progress_data)
public method	ReprojectImage (scalar src_ds, scalar dst_ds, scalar src_wkt=undef, scalar dst_wkt=undef, scalar ResampleAlg='NearestNeighbour', scalar WarpMemoryLimit=0, scalar maxerror=0.0, subref progress, scalar progress_data)
public list	ResamplingTypes ()
public scalar	SerializeXMLTree (arrayref XMLTree)
public method	SetCacheMax (scalar Bytes)
public method	SetConfigOption (scalar key, scalar value)
public method	SieveFilter (Geo::GDAL::Band src, Geo::GDAL::Band mask, Geo::GDAL::Band dst, scalar threshold, scalar connectedness, hashref options, subref progress, scalar progress_data)
public scalar	VersionInfo (scalar request= 'VERSION_NUM')

Detailed Description

GDAL utility functions and a root class for raster classes.

Geo::GDAL wraps many GDAL utility functions and acts as a root class for all GDAL raster classes. A "raster" is a dataset, whose core is a rectagular grid or grids of pixels, called a "band" in GDAL. Each pixel contains a numeric value of a specific data type

Definition at line 14 of file all.pm.

Member Function Documentation

public list Geo::GDAL::AccessTypes

(

)

Class method.

Returns

a list of GDAL data set open modes. These are currently: ReadOnly, and Update.

Code:

public Geo::GDAL::Dataset Geo::GDAL::AutoCreateWarpedVRT	(	Geo::GDAL::Dataset	src,
		Geo::OSR::SpatialReference	src_srs = undef,
		Geo::OSR::SpatialReference	dst_srs = undef,
		scalar	ResampleAlg = 'NearestNeighbour',
		scalar	maxerror = 0.0
	)

Class method.

Parameters

src
src_srs	source projection.
dst_srs	destination projection.
ResampleAlg	one of Geo::GDAL::ResamplingTypes().
maxerror

Returns

a new Geo::GDAL::Dataset object

Documentation for GDAL warper

Code:

public list Geo::GDAL::Child	(	scalar	node,
		scalar	i
	)

Class method.

Parameters

node
i	0 .. number of children - 1

Returns

Code:

public list Geo::GDAL::Children

(

scalar

node

)

Class method.

Parameters

node

Returns

Code:

public method Geo::GDAL::ComputeMedianCutPCT	(	Geo::GDAL::Band	red,
		Geo::GDAL::Band	green,
		Geo::GDAL::Band	blue,
		scalar	num_colors,
		scalar	colors,
		subref	progress,
		scalar	progress_data
	)

Class method. Compute an "optimal" color table for a three band image.

Parameters

red	a Geo::GDAL::Band object
green	a Geo::GDAL::Band object
blue	a Geo::GDAL::Band object
num_colors	the desired number of colors
colors	an empty Geo::GDAL::ColorTable object
progress	[optional] a reference to a subroutine, which will be called with parameters (number progress, string msg, progress_data)
progress_data	[optional]

Documentation for GDAL algorithms

Code:

public method Geo::GDAL::ComputeProximity	(	Geo::GDAL::Band	src,
		Geo::GDAL::Band	proximity,
		hashref	options,
		subref	progress,
		scalar	progress_data
	)

Class method.

Parameters

src	The raster from which the proximities are computed from.
proximity	The raster to which the proximities are computed to.
options	Options. Supported key, value pairs are VALUES => n[,n]* A list of target pixel values to measure the distance from. If this option is not provided proximity will be computed from non-zero pixel values. Currently pixel values are internally processed as integers. DISTUNITS => PIXEL|GEO Indicates whether distances will be computed in pixel units or in georeferenced units. The default is pixel units. This also determines the interpretation of MAXDIST. MAXDIST => n The maximum distance to search. Proximity distances greater than this value will not be computed. Instead output pixels will be set to a nodata value. NODATA => n The NODATA value to use on the output band for pixels that are beyond MAXDIST. If not provided, the hProximityBand will be queried for a nodata value. If one is not found, 65535 will be used. FIXED_BUF_VAL => n If this option is set, all pixels within the MAXDIST threadhold are set to this fixed value instead of to a proximity distance.
progress	[optional] a reference to a subroutine, which will be called with parameters (number progress, string msg, progress_data)
progress_data	[optional]

Documentation for GDAL algorithms

Code:

public method Geo::GDAL::CPLBinaryToHex

(

)

Code:

public method Geo::GDAL::CPLHexToBinary

(

)

Code:

public scalar Geo::GDAL::DataTypeIsComplex

(

scalar

DataType

)

Class method.

Parameters

DataType

A GDAL pixel data type (one of those listed by Geo::GDAL::DataTypes).

Returns

true if the data type is a complex number.

Code:

public list Geo::GDAL::DataTypes

(

)

Class method.

Returns

a list of GDAL pixel data types. These are currently: Byte, CFloat32, CFloat64, CInt16, CInt32, Float32, Float64, Int16, Int32, UInt16, UInt32, and Unknown.

Code:

public list Geo::GDAL::DataTypeValueRange

(

scalar

DataType

)

Class method.

Parameters

DataType

Data type (one of those listed by Geo::GDAL::DataTypes).

Note

Some returned values are inaccurate.

Returns

the minimum, maximum range of the data type.

Code:

public method Geo::GDAL::Debug

(

)

Code:

public scalar Geo::GDAL::DecToDMS	(	scalar	angle,
		scalar	axis,
		scalar	precision = 2
	)

Class method. Convert decimal degrees to degrees, minutes, and seconds string

Parameters

angle	A number
axis	A string specifying latitude or longitude ('Long').
precision

Returns

a string nndnn'nn.nn'"L where n is a number and L is either N or E

Code:

public scalar Geo::GDAL::DecToPackedDMS

(

scalar

dec

)

Class method.

Parameters

dec	Decimal degrees

Returns

packed DMS, i.e., a number DDDMMMSSS.SS

Code:

public method Geo::GDAL::DitherRGB2PCT	(	scalar	red,
		scalar	green,
		scalar	blue,
		scalar	target,
		scalar	colors,
		subref	progress,
		scalar	progress_data
	)

Class method. Dither a three band image into one band using a color table.

Parameters

red	a Geo::GDAL::Band object
green	a Geo::GDAL::Band object
blue	a Geo::GDAL::Band object
target	a Geo::GDAL::Band object
colors	a Geo::GDAL::ColorTable object
progress	[optional] a reference to a subroutine, which will be called with parameters (number progress, string msg, progress_data)
progress_data	[optional]

Documentation for GDAL algorithms

Code:

public method Geo::GDAL::EscapeString

(

)

Code:

public method Geo::GDAL::FinderClean

(

)

Class method. Clear the set of support file search paths.

Code:

public scalar Geo::GDAL::FindFile	(	scalar	class,
		scalar	basename
	)

Class method. Search for GDAL support files.

An example:

use Geo::GDAL;
$a = Geo::GDAL::FindFile('gdal', 'pcs.csv');
print STDERR "$a\n";

Prints (for example):

c:\msys\1.0\local\share\gdal\pcs.csv

Parameters

class	The class of files to search for. For example 'gdal'.
basename	The basename of the file to search for. For example 'pcs.csv'.

Returns

the path to the searched file or undef.

Code:

public scalar Geo::GDAL::GetCacheMax

(

)

Class method.

Returns

maximum amount of memory (as bytes) for caching within GDAL.

Code:

public scalar Geo::GDAL::GetCacheUsed

(

)

Class method.

Returns

the amount of memory currently used for caching within GDAL.

Code:

public scalar Geo::GDAL::GetConfigOption	(	scalar	key,
		scalar	default
	)

Class method.

Parameters

key	A GDAL config option.
default	A default value for the option.

Returns

the value of the GDAL config option or the value of the default parameter.

Code:

public scalar Geo::GDAL::GetDataTypeSize

(

scalar

DataType

)

Class method.

Parameters

DataType

A GDAL pixel data type (one of those listed by Geo::GDAL::DataTypes).

Returns

the size as the number of bits.

Code:

public Geo::GDAL::Driver Geo::GDAL::GetDriver

(

scalar

name

)

Class method. Create a driver object for the internal GDAL driver.

Parameters

name	the (short) name of the driver.

Returns

a Geo::GDAL::Driver object, which represents the internal driver.

Code:

public list Geo::GDAL::GetDriverNames

(

)

Class method.

Returns

a list of the named of all (available and registered) GDAL raster drivers.

Code:

public method Geo::GDAL::GetJPEG2000StructureAsString

(

)

Code:

public method Geo::GDAL::GOA2GetAccessToken

(

)

Code:

public method Geo::GDAL::GOA2GetAuthorizationURL

(

)

Code:

public method Geo::GDAL::GOA2GetRefreshToken

(

)

Code:

public Geo::GDAL::Driver Geo::GDAL::IdentifyDriver	(	scalar	path,
		scalar	siblings
	)

Class method.

Parameters

path	a dataset path.
siblings	[optional] A list of names of files in the directory specified by the path.

Returns

a Geo::GDAL::Driver object, which represents an internal driver.

Code:

public list Geo::GDAL::NodeData

(

scalar

node

)

Class method.

Parameters

node

Returns

($NodeType, $value)

Code:

public scalar Geo::GDAL::NodeType

(

scalar

type

)

Class method. Convert between integer and string expressions of CPLXMLNodeTypes

Parameters

type	(as integer)

Returns

type (as string)

Code:

public list Geo::GDAL::NodeTypes

(

)

Class method.

Returns

a list of GDAL XML parser node types. These are currently: Attribute, Comment, Element, Literal, and Text.

Code:

public Geo::GDAL::Dataset Geo::GDAL::Open	(	scalar	name,
		scalar	access = 'ReadOnly'
	)

Class method. An example

use Geo::GDAL;
$ds = Geo::GDAL::Open('existing.tiff', 'Update');

Parameters

name
access	Access type (one of those listed by Geo::GDAL::AccessTypes).

Returns

a new Geo::GDAL::Dataset object.

Code:

public Geo::GDAL::Dataset Geo::GDAL::OpenEx	(	scalar	name,
		scalar	open_flags = 0,
		array reference	allowed_drivers = undef,
		array reference	open_options = undef,
		array reference	sibling_files = undef
	)

Class method.

Returns

a new Geo::GDAL::Dataset object.

Code:

public Geo::GDAL::Dataset Geo::GDAL::OpenShared	(	scalar	name,
		scalar	access = 'ReadOnly'
	)

Class method.

Parameters

name
access	Access type (one of those listed by Geo::GDAL::AccessTypes).

Returns

a new Geo::GDAL::Dataset object.

Code:

public scalar Geo::GDAL::PackCharacter

(

scalar

DataType

)

Class method. Get the character that is needed for Perl's pack and unpack when they are used with Geo::GDAL::Band::ReadRaster and Geo::GDAL::Band::WriteRaster. Note that Geo::GDAL::Band::ReadTile and Geo::GDAL::Band::WriteTile have simpler interfaces that do not require pack and unpack.

Parameters

DataType

A GDAL pixel data type (typically from $band->{DataType}).

Returns

a character which can be used in Perl's pack and unpack.

Code:

public scalar Geo::GDAL::PackedDMSToDec

(

scalar

packed

)

Class method.

Parameters

packed

DMS as a number DDDMMMSSS.SS

Returns

decimal degrees

Code:

public array reference Geo::GDAL::ParseXMLString

(

scalar

XML

)

Class method. Parses a given XML into an array of arrays and returns a reference to that. An array in the structure is: (CPLXMLNodeType, value, child, child, ...). CPLXMLNodeType is an integer.

Parameters

XML

Returns

an XMLTree.

Example:

open FILE, "data.xml" or die "Couldn't open file: $!"; 
my $xml = join("", <FILE>); 
close FILE;
my $tree = Geo::GDAL::ParseXMLString($xml);
traverse($tree);
print Geo::GDAL::SerializeXMLTree($tree),"\n";

sub traverse {
.    my $node = shift;
.    my $type = shift @$node;
.    my $data = shift @$node;
.    $type = Geo::GDAL::NodeType($type); 
.    print "$type, $data\n";
.    for my $child (@$node) {
.        traverse($child);
.    }
}

Code:

public method Geo::GDAL::Polygonize	(	Geo::GDAL::Band	src,
		Geo::GDAL::Band	mask,
		Geo::OGR::Layer	out,
		scalar	PixValField,
		hashref	options,
		subref	progress,
		scalar	progress_data
	)

Class method.

Parameters

src
mask	All pixels in the mask band with a value other than zero will be considered suitable for collection as polygons. Must be undef if not used.
out
PixValField	The index (or name) of the field in output layer into which the pixel value of the polygon should be written.
options	Not used.
progress	[optional] a reference to a subroutine, which will be called with parameters (number progress, string msg, progress_data)
progress_data	[optional]

Documentation for GDAL algorithms

Code:

public method Geo::GDAL::PopFinderLocation

(

)

Class method. Remove the latest addition from the set of support file search paths.

Code:

public method Geo::GDAL::PushFinderLocation

(

scalar

path

)

Class method. Add a path to the set of paths from where GDAL support files are sought.

Code:

public method Geo::GDAL::RasterizeLayer	(	Geo::GDAL::Dataset	ds,
		arrayref	bands,
		Geo::OGR::Layer	layer,
		scalar	transformer,
		scalar	arg,
		arrayref	burn_values,
		hashref	options,
		subref	progress,
		scalar	progress_data
	)

Class method.

Parameters

ds
bands	A reference to a list of bands to be updated.
layer
transformer	Not supported, must be undef.
arg	Transformer argument, must be undef.
burn_values	Values to be used for burning the geometries. One for each layer.
options	Not used.
progress	[optional] a reference to a subroutine, which will be called with parameters (number progress, string msg, progress_data)
progress_data	[optional]

Documentation for GDAL algorithms

Code:

public method Geo::GDAL::ReprojectImage	(	scalar	src_ds,
		scalar	dst_ds,
		scalar	src_wkt = undef,
		scalar	dst_wkt = undef,
		scalar	ResampleAlg = 'NearestNeighbour',
		scalar	WarpMemoryLimit = 0,
		scalar	maxerror = 0.0,
		subref	progress,
		scalar	progress_data
	)

Class method.

Parameters

src_ds	Source dataset.
dst_ds	Destination dataset.
src_wkt	Source projection as a WKT.
dst_wkt	Destination projection as a WKT.
ResampleAlg	One of NearestNeighbour Bilinear Cubic or CubicSpline.
WarpMemoryLimit	The amount of memory allowed for caching. Default is 0, i.e., no limit.
maxerror	Maximum error measured in input pixels that is allowed in approximating the transformation. Default is 0.0, i.e., exact calculations.
progress	[optional] a reference to a subroutine, which will be called with parameters (number progress, string msg, progress_data). Reprojection is terminated if the progress function returns 0.
progress_data	[optional]

Documentation for GDAL warper

Code:

public list Geo::GDAL::ResamplingTypes

(

)

Class method.

Returns

a list of GDAL resampling methods.

Code:

public list Geo::GDAL::RIOResamplingTypes

(

)

Class method.

Returns

a list of GDAL raster IO resampling methods.

Code:

public scalar Geo::GDAL::SerializeXMLTree

(

arrayref

XMLTree

)

Class method.

Parameters

XMLTree

Returns

XML

Code:

public method Geo::GDAL::SetCacheMax

(

scalar

Bytes

)

Class method.

Parameters

Bytes

New maximum amount of memory for caching within GDAL.

Code:

public method Geo::GDAL::SetConfigOption	(	scalar	key,
		scalar	value
	)

Class method.

Parameters

key

A GDAL config option. Possible values include 'GDAL_FORCE_CACHING', 'USE_RRD', GDAL_DATA', 'GDAL_SKIP', 'GDAL_DRIVER_PATH', 'GDAL_IGNORE_AXIS_ORIENTATION', 'GMLJP2OVERRIDE', 'GDAL_DISABLE_READDIR_ON_OPEN', 'GDAL_PAM_ENABLED', 'GDAL_PAM_MODE', 'GDAL_PAM_PROXY_DIR', 'GDAL_MAX_DATASET_POOL_SIZE', 'GDAL_FORCE_CACHING', 'GDAL_CACHEMAX', 'GDAL_SWATH_SIZE', 'PROJSO', 'CENTER_LONG', 'OGR_DEBUG_ORGANIZE_POLYGONS', 'OGR_ORGANIZE_POLYGONS', and 'GDAL_JP2K_ALT_OFFSETVECTOR_ORDER'. Consult the GDAL main documentation for the semantics of config options.

value

A value for the option, typically 'YES', 'NO', undef, a path, or a filename.

Code:

public method Geo::GDAL::SieveFilter	(	Geo::GDAL::Band	src,
		Geo::GDAL::Band	mask,
		Geo::GDAL::Band	dst,
		scalar	threshold,
		scalar	connectedness,
		hashref	options,
		subref	progress,
		scalar	progress_data
	)

Class method. Removes small raster polygons.

Parameters

src
mask
dst
threshold	An integer.
connectedness	4 or 8
options	Not used.
progress	[optional] a reference to a subroutine, which will be called with parameters (number progress, string msg, progress_data)
progress_data	[optional]

Documentation for GDAL algorithms

Code:

public scalar Geo::GDAL::VersionInfo

(

scalar

request = 'VERSION_NUM'

)

Class method.

Parameters

request

A string specifying the request. Currently either "VERSION_NUM", "RELEASE_DATE", "RELEASE_NAME", or "--version". Default is "VERSION_NUM".

Returns

Requested information.

Code:

---

The documentation for this class was generated from the following file:

• all.pm