Hi,
how can I extract the centroids from polygons and transform them into a point vector layer ? I have tiny polygons as groundtruth data for a satellite image analysis and I would like to retrieve the centroids as points so that I can use v.what.rast, in order to obtain the spectral information for the groundtruth data.
Best regards
Niels
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Dr. Niels Thevs
Chair of Geobotany and Landscape Ecology
Institute of Botany and Landscape Ecology
Greifswald University
Grimmer Strasse 88
17487 Greifswald
Germany
Tel.: +49-3834-86-4132
Fax: +49-3834-86-4114
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On Mon, 2008-12-01 at 14:57 +0100, Niels Thevs wrote:
Hi,
how can I extract the centroids from polygons and transform them into a
point vector layer ? I have tiny polygons as groundtruth data for a
satellite image analysis and I would like to retrieve the centroids as
points so that I can use v.what.rast, in order to obtain the spectral
information for the groundtruth data.
Best regards
Niels
Hi Niels!
You probably need to use "v.extract type=centroid".
Regards, Nikos
On 01/12/08 14:57, Niels Thevs wrote:
Hi,
how can I extract the centroids from polygons and transform them into a point vector layer ? I have tiny polygons as groundtruth data for a satellite image analysis and I would like to retrieve the centroids as points so that I can use v.what.rast, in order to obtain the spectral information for the groundtruth data.
v.extract in=map_polygons type=centroid out=map_centroids
v.type in=map_centroids out=map_points type=centroid,point
Moritz