def set(self, cat, layer=1):
"""Add new field/cat to category structure if doesn't exist yet.
:param cat: the cat to add
:type cat: int
:param layer: the number of layer
:type layer: int
"""
libvect.Vect_cat_set(self.c_cats, layer, cat)
def rewrite(self, line, geo_obj, attrs=None, **kargs):
"""Rewrite a geometry features
"""
if self.table is not None and attrs:
attr = [
line,
]
attr.extend(attrs)
self.table.update(key=line, values=attr)
elif self.table is None and attrs:
print("Table for vector {name} does not exist, attributes not"
" loaded".format(name=self.name))
libvect.Vect_cat_set(geo_obj.c_cats, self.layer, line)
result = libvect.Vect_rewrite_line(self.c_mapinfo, line, geo_obj.gtype,
geo_obj.c_points, geo_obj.c_cats)
if result == -1:
raise GrassError("Not able to write the vector feature.")
# return offset into file where the feature starts
geo_obj.offset = result
def rewrite(self, geo_obj, cat, attrs=None, **kargs):
"""Rewrite a geometry features
>>> cols = [(u'cat', 'INTEGER PRIMARY KEY'),
... (u'name', 'TEXT')]
Generate a new vector map
>>> test_vect = VectorTopo('newvect_2')
>>> test_vect.open('w', tab_name='newvect_2', tab_cols=cols,
... overwrite=True)
import a geometry feature ::
>>> from grass.pygrass.vector.geometry import Point
create two points ::
>>> point0 = Point(0, 0)
>>> point1 = Point(1, 1)
>>> point2 = Point(2, 2)
then write the two points on the map, with ::
>>> test_vect.write(point0, cat=1, attrs=('pub',))
>>> test_vect.write(point1, cat=2, attrs=('resturant',))
>>> test_vect.table.conn.commit() # save changes in the DB
>>> test_vect.table_to_dict()
{1: [1, u'pub'], 2: [2, u'resturant']}
>>> test_vect.close()
Now rewrite one point of the vector map: ::
>>> test_vect.open('rw')
>>> test_vect.rewrite(point2, cat=1, attrs=('Irish Pub',))
>>> test_vect.table.conn.commit() # save changes in the DB
>>> test_vect.close()
Check the output:
>>> test_vect.open('r')
>>> test_vect[1] == point2
True
>>> test_vect[1].attrs['name'] == 'Irish Pub'
True
>>> test_vect.close()
>>> test_vect.remove()
"""
if self.table is not None and attrs:
self.table.update(key=cat, values=attrs)
elif self.table is None and attrs:
print("Table for vector {name} does not exist, attributes not"
" loaded".format(name=self.name))
libvect.Vect_cat_set(geo_obj.c_cats, self.layer, cat)
result = libvect.Vect_rewrite_line(self.c_mapinfo,
cat, geo_obj.gtype,
geo_obj.c_points,
geo_obj.c_cats)
if result == -1:
raise GrassError("Not able to write the vector feature.")
# return offset into file where the feature starts
geo_obj.offset = result