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Geo-GDAL-FFI-0.01
River stage one • 1 direct dependent • 2 total dependents
2 ++
/ Geo::GDAL::FFI

NAME

Geo::GDAL::FFI - A foreign function interface to GDAL

SYNOPSIS

    use Geo::GDAL::FFI;
    my $gdal = Geo::GDAL::FFI->new();

    my $sr = Geo::GDAL::FFI::SpatialReference->new(EPSG => 3067);
    my $layer = $gdal
        ->GetDriver('ESRI Shapefile')
        ->Create('test.shp')
        ->CreateLayer({
            Name => 'test',
            SpatialReference => $sr,
            GeometryType => 'Point',
            Fields => [
            {
                Name => 'name',
                Type => 'String'
            }
            ]
        });
    my $f = Geo::GDAL::FFI::Feature->new($layer->Defn);
    $f->SetField(name => 'a');
    my $g = Geo::GDAL::FFI::Geometry->new('Point');
    $g->SetPoint(1, 2);
    $f->SetGeomField($g);
    $layer->CreateFeature($f);

    undef $layer; # this flushes and closes the shapefile files

    $layer = $gdal->Open('test.shp')->GetLayer;
    $layer->ResetReading;
    while (my $feature = $layer->GetNextFeature) {
        my $value = $feature->GetField('name');
        my $geom = $feature->GetGeomField;
        say $value, ' ', $geom->AsText;
    }

DESCRIPTION

This is a foreign function interface to the GDAL geospatial data access library.

Methods

'$named_arguments' below means a reference to a hash whose keys are argument names.

The progress function parameter used in many methods should be a reference to a subroutine. The subroutine is called with three parameters ($fraction, $msg, $data), where $fraction is a number, $msg is a string, and $data is a pointer that is given as the progress data parameter.

new

Create a new Geo::GDAL::FFI object.

Capabilities

Returns the list of capabilities (strings) an Object can have.

OpenFlags

Returns the list of opening flags to be used in the Open method.

DataTypes

Returns the list of raster cell data types to be used in e.g. the CreateDataset method of the Driver class.

FieldTypes

Returns the list of field types.

FieldSubtypes

Returns the list of field subtypes.

Justifications

Returns the list of field justifications.

ColorInterpretations

Returns the list of color interpretations.

GeometryTypes

Returns the list of geometry types.

GetVersionInfo

Returns version information from the underlying GDAL library.

GetDrivers

Returns a list of all available driver objects.

GetDriver($name)

Returns the specific driver object.

Open($name, $named_arguments)

Open a dataset. $name is the name of the dataset. Named arguments are the following.

Flags

Optional, default is a reference to an empty array.

AllowedDrivers

Optional, default is all drivers. Use a reference to an array of driver names to limit drivers to test.

SiblingFiles

Optional, default is to probe the file system. You may use a reference to an array of auxiliary file names.

Options

Optional, a reference to an array of driver specific open options.

Geo::GDAL::FFI::Object

The base class for classes Driver, SpatialReference, Dataset, Band, and Layer.

Methods

GetDescription
HasCapability($capability)
GetMetadataDomainList
GetMetadata($domain)
SetMetadata($metadata, $domain)
GetMetadataItem($item, $domain)
SetMetadataItem($item, $value, $domain)

Geo::GDAL::FFI::Driver

A format driver. Use the Driver method of a Geo::GDAL::FFI object to obtain one.

Methods

GetName

Returns the name of the driver.

Create($name, $named_arguments)

Create a dataset. $name is the name for the dataset to create.

Named arguments are the following.

Width

Optional, but required to create a raster dataset.

Height

Optional, default is the same as width.

Bands

Optional, the number of raster bands in the dataset, default is one.

DataType

Optional, the data type (string) for the raster cells, default is 'Byte'.

Source

Optional, the dataset to copy.

Progress

Optional, used only in dataset copy, a reference to a subroutine.

ProgressData

Optional, used only in dataset copy, a reference.

Strict

Optional, used only in dataset copy, default is false (0).

Options

Optional, driver specific creation options, default is reference to an empty hash.

Create($name, $width, $height)

A simple syntax for calling Create to create a raster dataset.

Geo::GDAL::FFI::SpatialReference

Methods

new($arg, @args)

Create a new SpatialReference object. If only one argument is given, it is taken as the well known text (WKT) associated with the spatial reference system (SRS). If there are more than one argument, the first argument is taken as a format and the rest of the arguments are taken as arguments to the format. The list of formats known to GDAL (at the time of this writing) is EPSG, EPSGA, Wkt, Proj4, ESRI, PCI, USGS, XML, Dict, Panorama, Ozi, MICoordSys, ERM, Url.

Export($format, @args)

Export a SpatialReference object to a format. The list of formats known to GDAL (at the time of this writing) is Wkt, PrettyWkt, Proj4, PCI, USGS, XML, Panorama, MICoordSys, ERM.

Set($setter, @args)

Set projection parameters in a SpatialReference object. The list of projection parameters known to GDAL (at the time of this writing) is Axes, ACEA, AE, Bonne, CEA, CS, EC, Eckert, EckertIV, EckertVI, Equirectangular, Equirectangular2, GS, GH, IGH, GEOS, GaussSchreiberTMercator, Gnomonic, HOM, HOMAC, HOM2PNO, IWMPolyconic, Krovak, LAEA, LCC, LCC1SP, LCCB, MC, Mercator, Mercator2SP, Mollweide, NZMG, OS, Orthographic, Polyconic, PS, Robinson, Sinusoidal, Stereographic, SOC, TM, TMVariant, TMG, TMSO, TPED, VDG, Wagner, QSC, SCH

Geo::GDAL::FFI::Dataset

Obtain a dataset object by opening it with the Open method of Geo::GDAL::FFI object or by creating it with the Create method of a Driver object.

Methods

GetDriver
GetInfo(@options)
Translate($name, @options)

Convert a raster dataset into another raster dataset. $name is the name of the target dataset. This is the same as the gdal_translate command line program, so the options are the same. See http://www.gdal.org/gdal_translate.html.

GetWidth =item GetHeight =item GetSize

Returns the size (width, height) of the bands of this raster dataset.

GetBand =item GetBands

Returns a list of Band objects representing the bands of this raster dataset.

CreateLayer($named_arguments)

Create a new vector layer into this vector dataset.

Named arguments are the following.

Name

Optional, string, default is ''.

GeometryType

Optional, default is 'Unknown', the type of the first geometry field; note: if type is 'None', the layer schema does not initially contain any geometry fields.

SpatialReference

Optional, a SpatialReference object, the spatial reference for the first geometry field.

Options

Optional, driver specific options in an anonymous hash.

Fields

Optional, a reference to an array of Field objects or schemas, the fields to create into the layer.

GeometryFields

Optional, a reference to an array of GeometryField objects or schemas, the geometry fields to create into the layer; note that if this argument is defined then the arguments GeometryType and SpatialReference are ignored.

GetLayer($name)

If $name is strictly an integer, then returns the (name-1)th layer in the dataset, otherwise returns the layer whose name is $name. Without arguments returns the first layer.

CopyLayer($layer, $name, $options)

Geo::GDAL::FFI::Band

A band (channel) in a raster dataset. Use the Band method of a dataset object to obtain a band object.

Methods

GetDataType
GetSize
GetBlockSize
GetNoDataValue
SetNoDataValue
Read($xoff, $yoff, $xsize, $ysize, $bufxsize, $bufysize)
ReadBlock($xoff, $yoff)
Write($data, $xoff, $yoff, $xsize, $ysize)
WriteBlock($data, $xoff, $yoff)
GetColorInterpretation
SetColorInterpretation
GetColorTable
SetColorTable
SetPiddle($pdl, $xoff, $yoff, $xsize, $ysize)

Read data from a piddle into this Band.

GetPiddle($xoff, $yoff, $xsize, $ysize, $xdim, $ydim)

Read data from this Band into a piddle.

Geo::GDAL::FFI::Layer

A set of (vector) features having a same schema (the same Defn object). Obtain a layer object by the CreateLayer or GetLayer method of a vector dataset object.

Methods

GetDefn

Returns the FeatureDefn object for this layer.

ResetReading
GetNextFeature
GetFeature
SetFeature
CreateFeature
DeleteFeature

Geo::GDAL::FFI::FeatureDefn

Methods

new($named_arguments)

Create a new FeatureDefn object.

The named arguments (optional) are the following.

GetName

Optional; the name for this feature class; default is the empty string.

Fields

Optional, a reference to an array of FieldDefn objects or schemas.

GeometryFields

Optional, a reference to an array of GeomFieldDefn objects or schemas.

GeometryType

Optional, the type for the first geometry field; default is Unknown. Note that this argument is ignored if GeometryFields is given.

StyleIgnored
GetSchema

Returns the definition as a perl data structure.

GetFieldDefn($name)

Get the specified non spatial field object. If the argument is explicitly an integer and not a string, it is taken as the field index.

GetFieldDefns
GetGeomFieldDefn($name)

Get the specified spatial field object. If the argument is explicitly an integer and not a string, it is taken as the field index.

GetGeomFieldDefns
SetGeometryIgnored($arg)

Ignore the first geometry field when reading features from a layer. To not ignore the first geometry field call this method with defined but false (0) argument.

IsGeometryIgnored

Is the first geometry field ignored when reading features from a layer.

Geo::GDAL::FFI::FieldDefn

There should not usually be any reason to directly access this method except for the ignore methods. This object is created/read from/to the Perl data structure in the CreateLayer method of a dataset, or in the constructor or schema method of FeatureDefn.

Schema

The schema of a FieldDefn is (Name, Type, Default, Subtype, Justify, Width, Precision, NotNullable).

Methods

SetIgnored($arg)

Ignore this field when reading features from a layer. To not ignore this field call this method with defined but false (0) argument.

IsIgnored

Is this field ignored when reading features from a layer.

Geo::GDAL::FFI::GeomFieldDefn

There should not usually be any reason to directly access this method except for the ignore methods. This object is created/read from/to the Perl data structure in the CreateLayer method of a dataset, or in the constructor or schema method of FeatureDefn.

Schema

The schema of a GeomFieldDefn is (Name, Type, SpatialReference, NotNullable).

Methods

SetIgnored($arg)

Ignore this field when reading features from a layer. To not ignore this field call this method with defined but false (0) argument.

IsIgnored

Is this field ignored when reading features from a layer.

Geo::GDAL::FFI::Feature

Methods

new($defn)

Create a new Feature object. The argument is a FeatureDefn object, which you can get from a Layer object (Defn method), another Feature object (Defn method), or by explicitly creating a new FeatureDefn object.

GetDefn

Returns the FeatureDefn object for this Feature.

GetFID
SetFID
Clone
Equals($feature)
SetField($fname, ...)

Set the value of field $fname. If no parameters after the name is given, the field is unset. If the parameters after the name is undefined, sets the field to NULL. Otherwise sets the field according to the field type.

GetField($fname)
SetGeomField($fname, $geom)

$fname is optional and by default the first geometry field.

GetGeomField($fname)

$fname is optional and by default the first geometry field.

Geo::GDAL::FFI::Geometry

Methods

new($type)

$type must be one of Geo::GDAL::FFI::GeometryTypes().

new($format, $arg, $sr)

$format must be one of Geo::GDAL::FFI::GeometryFormats(), e.g., 'WKT'.

$sr should be a SpatialRef object if given.

Clone

Clones this geometry and returns the clone.

GetType($mode)

Returns the type of this geometry. If $mode is 'flatten', returns the type without Z, M, or ZM postfix.

GetPointCount

Returns the point count of this geometry.

SetPoint($x, $y, $z, $m)

Set the coordinates of a point geometry. The usage of $z and $m in the method depend on the actual 3D or measured status of the geometry.

SetPoint($coords)

$coords = [$x, $y, $z, $m]

Set the coordinates of a point geometry. The usage of $z and $m in the method depend on the actual 3D or measured status of the geometry.

SetPoint($i, $x, $y, $z, $m)

Set the coordinates of the ith (zero based index) point in a curve geometry. The usage of $z and $m in the method depend on the actual 3D or measured status of the geometry.

Note that setting the nth point of a curve may create all points 0..n-2.

SetPoint($i, $coords)

Set the coordinates of the ith (zero based index) point in this curve. $coords must be a reference to an array of the coordinates. The usage of $z and $m in the method depend on the 3D or measured status of the geometry.

Note that setting the nth point of a curve may create all points 0..n-2.

GetPoint($i)

Get the coordinates of the ith (zero based index) point in this curve. This method can also be used to set the coordinates of a point geometry and then the $i must be zero if it is given.

Returns the coordinates either as a list or a reference to an anonymous array depending on the context. The coordinates contain $z and $m depending on the 3D or measured status of the geometry.

GetPoints

Returns the coordinates of the vertices of this geometry in an obvious array based data structure. Note that different geometry types have similar data structures.

SetPoints($points)

Sets the coordinates of the vertices of this geometry from an obvious array based data structure. Note that different geometry types have similar data structures. If the geometry contains subgeometries (like polygon contains rings for example) the data structure is assumed to adhere to this structure. Uses SetPoint and may thus add points to curves.

GetGeometryCount
GetGeometry($i)

Returns the ith subgeometry (zero based index) in this geometry. The returned geometry object is only a wrapper to the underlying C++ reference and thus changing that geometry will change the parent.

AddGeometry($geom)
RemoveGeometry($i)
AsText
Intersects
Equals
Disjoint
Touches
Crosses
Within
Contains
Overlaps
Boundary
ConvexHull
Buffer
Intersection
Union
Difference
SymDifference
Distance
Distance3D
Length
Area
Centroid
Empty
IsEmpty
IsValid
IsSimple
IsRing

LICENSE

This software is released under the Artistic License. See perlartistic.

AUTHOR

Ari Jolma - Ari.Jolma at gmail.com

SEE ALSO

Alien::gdal, FFI::Platypus, www.gdal.org