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1 """ |
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2 Utilities for manipulating Geometry WKT. |
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3 """ |
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4 |
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5 def precision_wkt(geom, prec): |
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6 """ |
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7 Returns WKT text of the geometry according to the given precision (an |
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8 integer or a string). If the precision is an integer, then the decimal |
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9 places of coordinates WKT will be truncated to that number: |
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10 |
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11 >>> pnt = Point(5, 23) |
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12 >>> pnt.wkt |
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13 'POINT (5.0000000000000000 23.0000000000000000)' |
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14 >>> precision(geom, 1) |
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15 'POINT (5.0 23.0)' |
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16 |
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17 If the precision is a string, it must be valid Python format string |
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18 (e.g., '%20.7f') -- thus, you should know what you're doing. |
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19 """ |
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20 if isinstance(prec, int): |
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21 num_fmt = '%%.%df' % prec |
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22 elif isinstance(prec, basestring): |
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23 num_fmt = prec |
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24 else: |
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25 raise TypeError |
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26 |
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27 # TODO: Support 3D geometries. |
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28 coord_fmt = ' '.join([num_fmt, num_fmt]) |
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29 |
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30 def formatted_coords(coords): |
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31 return ','.join([coord_fmt % c[:2] for c in coords]) |
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32 |
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33 def formatted_poly(poly): |
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34 return ','.join(['(%s)' % formatted_coords(r) for r in poly]) |
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35 |
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36 def formatted_geom(g): |
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37 gtype = str(g.geom_type).upper() |
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38 yield '%s(' % gtype |
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39 if gtype == 'POINT': |
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40 yield formatted_coords((g.coords,)) |
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41 elif gtype in ('LINESTRING', 'LINEARRING'): |
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42 yield formatted_coords(g.coords) |
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43 elif gtype in ('POLYGON', 'MULTILINESTRING'): |
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44 yield formatted_poly(g) |
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45 elif gtype == 'MULTIPOINT': |
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46 yield formatted_coords(g.coords) |
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47 elif gtype == 'MULTIPOLYGON': |
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48 yield ','.join(['(%s)' % formatted_poly(p) for p in g]) |
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49 elif gtype == 'GEOMETRYCOLLECTION': |
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50 yield ','.join([''.join([wkt for wkt in formatted_geom(child)]) for child in g]) |
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51 else: |
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52 raise TypeError |
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53 yield ')' |
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54 |
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55 return ''.join([wkt for wkt in formatted_geom(geom)]) |