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<p class="MsoNormal"><span lang="EN-GB">Dear devs,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">After searching the pygrass documentation for examples on how to write areas to a vector map and trying different things without success, I am currently struggling with adding the category to the area.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Anyone, who can give me a hint on how add categories to a pygrass geometry, esp. area?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">The following Python code shows how I write the area (maybe it is supposed to be done differently?). Result is an area written, but without category and thus not usable at that point:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">import grass.script as grass<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">from grass.pygrass.vector import VectorTopo<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">from grass.pygrass.vector.geometry import Boundary<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">from grass.pygrass.vector.geometry import Centroid<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">from grass.pygrass.vector.geometry import Point<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"># Create area<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">area = Point(x=100, y=100).buffer(50)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">vect_name = 'test1'<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"># Create vector map<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">vect = VectorTopo(vect_name)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">vect.open(mode='w')<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">vect.write(Boundary(points=area[0].to_list()))<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"># , c_cats=int(cat), set_cats=True<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">cent = Centroid(x=area[1].x, y=area[1].y)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">vect.write(cent)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">vect.close(build=True)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"># Check if cat is present<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">grass.read_command('v.category', input= vect_name, option='report')<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Thanks for any hints in advance!<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Cheers<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Stefan<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">P.S.: Adding a category to the centroid does not help…<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">P.S.: BTW. pygrass documentation says area.buffer(50) is supposed to return an Area() object [1]. However, it returns a tuple with a line (boundary) and a point (centroid), like Area().buffer(50) is supposed to [2].<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">1: <a href="https://grass.osgeo.org/grass74/manuals/libpython/pygrass.vector.html#pygrass.vector.geometry.Point.buffer">
https://grass.osgeo.org/grass74/manuals/libpython/pygrass.vector.html#pygrass.vector.geometry.Point.buffer</a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">2: <a href="https://grass.osgeo.org/grass74/manuals/libpython/pygrass.vector.html#pygrass.vector.geometry.Area.buffer">
https://grass.osgeo.org/grass74/manuals/libpython/pygrass.vector.html#pygrass.vector.geometry.Area.buffer</a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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