[GRASS-user] Polygon2Point

GRASS GRASS user
1

hi,
i need a little help!
How can to export a point shapefile from a polygon layer in Grass (Convert
Polygon2Point)?
So, i can have in table (point file) all informations of the layer polygon
table!

Sorry my english!

Thanks!

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2

På 2007-05-22, skrev Salvator*eL*arosa:

hi,
i need a little help!
How can to export a point shapefile from a polygon layer in Grass (Convert
Polygon2Point)?
So, i can have in table (point file) all informations of the layer polygon
table!

Sorry my english!

Thanks!

In GRASS terminology polygons can be lines, boundaries, or areas (when
conbined with a centroid [= center point]). So assuming you have areas
and you want to export just the centroids, I believe something like:

v.type type=centroid,point in=mymap out=mymap_converted
v.out.ogr in=mymap_converted dsn=myshapefile.shp

would meet your needs.

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3

hajhouse wrote:

På 2007-05-22, skrev Salvator*eL*arosa:

hi,
i need a little help!
How can to export a point shapefile from a polygon layer in Grass
(Convert
Polygon2Point)?
So, i can have in table (point file) all informations of the layer
polygon
table!

Sorry my english!

Thanks!

In GRASS terminology polygons can be lines, boundaries, or areas (when
conbined with a centroid [= center point]). So assuming you have areas
and you want to export just the centroids, I believe something like:

v.type type=centroid,point in=mymap out=mymap_converted
v.out.ogr in=mymap_converted dsn=myshapefile.shp

would meet your needs.

Thank u for reply!

Unfortunately it doesn't work, yet. It export always shp polygon!
I need of a point shapefile!

However, I have resolved in different way.....
exporting in ASCII text file the coordinates of the centroids
and then importing it in QGIS with "delimited text", but without
attributes.

bye
--
View this message in context: http://www.nabble.com/Polygon2Point-tf3797481.html#a10764310
Sent from the Grass - Users mailing list archive at Nabble.com.

4

On 23/05/07 15:50, Salvator*eL*arosa wrote:

hajhouse wrote:

På 2007-05-22, skrev Salvator*eL*arosa:

hi,
i need a little help!
How can to export a point shapefile from a polygon layer in Grass
(Convert
Polygon2Point)?
So, i can have in table (point file) all informations of the layer
polygon
table!

Sorry my english!

Thanks!

In GRASS terminology polygons can be lines, boundaries, or areas (when
conbined with a centroid [= center point]). So assuming you have areas
and you want to export just the centroids, I believe something like:

v.type type=centroid,point in=mymap out=mymap_converted
v.out.ogr in=mymap_converted dsn=myshapefile.shp

would meet your needs.

Thank u for reply!

Unfortunately it doesn't work, yet. It export always shp polygon!
I need of a point shapefile!

You need to use the type= option of v.out.ogr:

v.type type=centroid,point in=mymap out=mymap_converted
v.out.ogr in=mymap_converted dsn=myshapefile.shp type=point

Then you get a point file with attributes.

Moritz