+
−"""
+
− Utilities for manipulating Geometry WKT.
+
−"""
+
−
+
−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:
+
−
+
−     >>> pnt = Point(5, 23)
+
−     >>> pnt.wkt
+
−     'POINT (5.0000000000000000 23.0000000000000000)'
+
−     >>> precision(geom, 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, basestring):
+
−        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)])