[GRASS-user] Creating a new vector map with pygrass

[Asim]

Hello!

Here is yet another request for hand-holding with GRASS GIS.  This time 
it's aquestion on pygrass API, version 7.8.5.  I want to create a new 
vector map from a Python script.  The steps I'm following are:

1. Create a VectorTopo object with.

2. Define attribute columns: cols = [(column name, type), ...]

3. Open the VectorTopo object in write mode: write("w", tab_cols=cols, ...).

4. Add geometry objects, in my case it's Area objects, one by one using 
write() interface.

5. Commit changes and close the VectorTopo.

Step 4, however, is causing "AttributeError" in a pygrass module.  Stack 
trace:

Traceback (most recent call last):
   File "stream_features.py", line 404, in <module>
     generateWatersheds(ssegs, dwsmapname)
   File "stream_features.py", line 359, in generateWatersheds
     dwsvector.write(
   File 
"/Applications/GRASS-7.8.app/Contents/Resources/etc/python/grass/pygrass/errors.py", 
line 15, in wrapper
     return method(self, *args, **kargs)
   File 
"/Applications/GRASS-7.8.app/Contents/Resources/etc/python/grass/pygrass/vector/__init__.py", 
line 217, in write
     result = self._write_area(geo_obj)
AttributeError: 'VectorTopo' object has no attribute '_write_area'

Can someone shed light on where my understanding is going wrong?  Is 
this a bug in vector/__init__.py?  The code snippet for reference:

<snip>

     dwsvector = vector.VectorTopo("differential_watersheds")

     dwscols = [("cat", "INTEGER PRIMARY KEY"),
                ("stream1", "INTEGER"),
                ("stream2", "INTEGER")]

     dwsvector.open("w", tab_name=dwsmapname, tab_cols=dwscols, 
overwrite=True)

     cat = 1

     # "boundary" is a vector.geometry.Boundary object, obtained
     # from an existing vector map that is opened previously.
     areageom = vector.geometry.Area(v_id=boundary.id, 
c_mapinfo=boundary.c_mapinfo)

     dwsvector.write(
         areageom,
         cat,
         attrs=(boundary.attrs["s1"], boundary.attrs["s2"]))

     # The AttributeError thrown when the write() method above is invoked.

</snip>

Hope the problem description is clear, if it isn't, please let me know.

Asim
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