Creating a vector dataset

The code here does not have any warranty. It is recommended that before using any of this code, you look into it and try to understand what it does, what input it needs, etc. Do not blindly execute anything!

This example creates a new layer to a named datasource. The layer will contain polygon features and each feature will contain an integer as an attribute value. The name of the attribute will be 'key'. Each polygon will have four vertices. The SRS is explicitly set to WGS84.

use Geo::GDAL;

# information that we need:
$dsname = ".";          # name of the datasource (in this case a directory)
$lname = "boxes";        # name of the layer
@data;                   # array which contains the data as hashref items,
                         # each item comprises items 'points' and 'key'
                         # 'points' is in this case an array of four points
                         # which are refs to arrays (x,y)
                         # 'key' is an integer which is stored as each
                         # feature's attribute data

@data = ({key => 'rect1', points => [[0,0],[1,0],[1,1],[0,1]]},
         {key => 'rect2', points => [[5,5],[7,5],[7,6],[5,6]]});

$datasource = Geo::OGR::Driver('ESRI Shapefile')->Create($dsname) or die;

$osr = new Geo::OSR::SpatialReference;
$osr->SetWellKnownGeogCS('WGS84');

$layer = $datasource->CreateLayer({ Name => $lname, SRS => $osr, GeometryType => 'Polygon'});
$layer->Schema( Fields => 
                [{ Name => 'key', Type => 'Integer' }] );

# make sure the cells share the points

for $item (@data) {

    @ring = ($item->{points}[0], 
             $item->{points}[1], 
             $item->{points}[2], 
             $item->{points}[3],
             $item->{points}[0]);

    $layer->InsertFeature({ 
        key => $item->{key},
        Geometry => { Points => [ \@ring ] }
    });

}

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