diff options
Diffstat (limited to 'webapp/django/contrib/gis/utils/wkt.py')
-rw-r--r-- | webapp/django/contrib/gis/utils/wkt.py | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/webapp/django/contrib/gis/utils/wkt.py b/webapp/django/contrib/gis/utils/wkt.py new file mode 100644 index 0000000000..4aecc6247d --- /dev/null +++ b/webapp/django/contrib/gis/utils/wkt.py @@ -0,0 +1,55 @@ +""" + 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)]) |