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- """
- Utilities for manipulating Geometry WKT.
- """
-
- from django.utils import six
-
-
- def precision_wkt(geom, prec):
- """
- Returns WKT text of the geometry according to the given precision (an
- integer or a string). If the precision is an integer, then the decimal
- places of coordinates WKT will be truncated to that number:
-
- >>> from django.contrib.gis.geos import Point
- >>> pnt = Point(5, 23)
- >>> pnt.wkt
- 'POINT (5.0000000000000000 23.0000000000000000)'
- >>> precision_wkt(pnt, 1)
- 'POINT (5.0 23.0)'
-
- If the precision is a string, it must be valid Python format string
- (e.g., '%20.7f') -- thus, you should know what you're doing.
- """
- if isinstance(prec, int):
- num_fmt = '%%.%df' % prec
- elif isinstance(prec, six.string_types):
- num_fmt = prec
- else:
- raise TypeError
-
- # TODO: Support 3D geometries.
- coord_fmt = ' '.join([num_fmt, num_fmt])
-
- def formatted_coords(coords):
- return ','.join(coord_fmt % c[:2] for c in coords)
-
- def formatted_poly(poly):
- return ','.join('(%s)' % formatted_coords(r) for r in poly)
-
- def formatted_geom(g):
- gtype = str(g.geom_type).upper()
- yield '%s(' % gtype
- if gtype == 'POINT':
- yield formatted_coords((g.coords,))
- elif gtype in ('LINESTRING', 'LINEARRING'):
- yield formatted_coords(g.coords)
- elif gtype in ('POLYGON', 'MULTILINESTRING'):
- yield formatted_poly(g)
- elif gtype == 'MULTIPOINT':
- yield formatted_coords(g.coords)
- elif gtype == 'MULTIPOLYGON':
- yield ','.join('(%s)' % formatted_poly(p) for p in g)
- elif gtype == 'GEOMETRYCOLLECTION':
- yield ','.join(''.join(wkt for wkt in formatted_geom(child)) for child in g)
- else:
- raise TypeError
- yield ')'
-
- return ''.join(wkt for wkt in formatted_geom(geom))
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