| """ |
| 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)]) |
