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