SF.net SVN: matplotlib: [4225] trunk/toolkits/basemap-testing/lib/shapely

[<js...@us...>]

Revision: 4225
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=4225&view=rev
Author:   jswhit
Date:     2007-11-12 08:51:08 -0800 (Mon, 12 Nov 2007)

Log Message:
-----------
add Shapely

Added Paths:
-----------
    trunk/toolkits/basemap-testing/lib/shapely/geos.py
    trunk/toolkits/basemap-testing/lib/shapely/iterops.py
    trunk/toolkits/basemap-testing/lib/shapely/predicates.py
    trunk/toolkits/basemap-testing/lib/shapely/topology.py
    trunk/toolkits/basemap-testing/lib/shapely/wkb.py
    trunk/toolkits/basemap-testing/lib/shapely/wkt.py

Added: trunk/toolkits/basemap-testing/lib/shapely/geos.py
===================================================================
--- trunk/toolkits/basemap-testing/lib/shapely/geos.py	                        (rev 0)
+++ trunk/toolkits/basemap-testing/lib/shapely/geos.py	2007-11-12 16:51:08 UTC (rev 4225)
@@ -0,0 +1,47 @@
+"""
+Exports the libgeos_c shared lib, GEOS-specific exceptions, and utilities.
+"""
+
+import atexit
+from ctypes import CDLL, CFUNCTYPE, c_char_p
+from ctypes.util import find_library
+import sys
+
+from find_geoslib import find_geoslib
+lgeos = find_geoslib()
+
+# Exceptions
+
+class ReadingError(Exception):
+    pass
+
+class DimensionError(Exception):
+    pass
+
+class TopologicalError(Exception):
+    pass
+
+class PredicateError(Exception):
+    pass
+
+
+# GEOS error handlers, which currently do nothing.
+
+def error_handler(fmt, list):
+    pass
+error_h = CFUNCTYPE(None, c_char_p, c_char_p)(error_handler)
+
+def notice_handler(fmt, list):
+    pass
+notice_h = CFUNCTYPE(None, c_char_p, c_char_p)(notice_handler)
+
+# Register a cleanup function
+
+def cleanup():
+    lgeos.finishGEOS()
+
+atexit.register(cleanup)
+
+lgeos.initGEOS(notice_h, error_h)
+
+

Added: trunk/toolkits/basemap-testing/lib/shapely/iterops.py
===================================================================
--- trunk/toolkits/basemap-testing/lib/shapely/iterops.py	                        (rev 0)
+++ trunk/toolkits/basemap-testing/lib/shapely/iterops.py	2007-11-12 16:51:08 UTC (rev 4225)
@@ -0,0 +1,54 @@
+"""
+"""
+
+from ctypes import c_char_p, c_size_t
+from shapely.geos import lgeos
+
+
+def geos_from_geometry(geom):
+    data = geom.to_wkb()
+    return lgeos.GEOSGeomFromWKB_buf(
+                        c_char_p(data),
+                        c_size_t(len(data))
+                        )
+
+class BinaryPredicateIterator(object):
+    
+    """A generating non-data descriptor.
+    """
+   
+    fn = None
+    context = None
+
+    def __init__(self, fn):
+        self.fn = fn
+
+    def __get__(self, obj, objtype=None):
+        self.context = obj
+        return self
+
+    def __call__(self, geom, iterator, value=True):
+        geos_geom = geos_from_geometry(geom)
+        for item in iterator:
+            try:
+                geom, ob = item
+            except TypeError:
+                geom = item
+                ob = geom
+            retval = self.fn(geos_geom, geos_from_geometry(geom))
+            if retval == 2:
+                raise PredicateError, "Failed to evaluate %s" % repr(self.fn)
+            elif bool(retval) == value:
+                yield ob
+
+
+# utilities
+disjoint = BinaryPredicateIterator(lgeos.GEOSDisjoint)
+touches = BinaryPredicateIterator(lgeos.GEOSTouches)
+intersects = BinaryPredicateIterator(lgeos.GEOSIntersects)
+crosses = BinaryPredicateIterator(lgeos.GEOSCrosses)
+within = BinaryPredicateIterator(lgeos.GEOSWithin)
+contains = BinaryPredicateIterator(lgeos.GEOSContains)
+overlaps = BinaryPredicateIterator(lgeos.GEOSOverlaps)
+equals = BinaryPredicateIterator(lgeos.GEOSEquals)
+

Added: trunk/toolkits/basemap-testing/lib/shapely/predicates.py
===================================================================
--- trunk/toolkits/basemap-testing/lib/shapely/predicates.py	                        (rev 0)
+++ trunk/toolkits/basemap-testing/lib/shapely/predicates.py	2007-11-12 16:51:08 UTC (rev 4225)
@@ -0,0 +1,50 @@
+"""
+Support for GEOS spatial predicates.
+"""
+
+from shapely.geos import PredicateError
+
+# Predicates
+
+class BinaryPredicate(object):
+    
+    """A callable non-data descriptor.
+    """
+   
+    fn = None
+    context = None
+
+    def __init__(self, fn):
+        self.fn = fn
+
+    def __get__(self, obj, objtype=None):
+        self.context = obj
+        return self
+
+    def __call__(self, other):
+        retval = self.fn(self.context._geom, other._geom)
+        if retval == 2:
+            raise PredicateError, "Failed to evaluate %s" % repr(self.fn)
+        return bool(retval)
+
+
+# A data descriptor
+class UnaryPredicate(object):
+
+    """A data descriptor.
+    """
+
+    fn = None
+
+    def __init__(self, fn):
+        self.fn = fn
+
+    def __get__(self, obj, objtype=None):
+        retval = self.fn(obj._geom)
+        if retval == 2:
+            raise PredicateError, "Failed to evaluate %s" % repr(self.fn)
+        return bool(retval)
+    
+    def __set__(self, obj, value=None):
+        raise AttributeError, "Attribute is read-only"
+

Added: trunk/toolkits/basemap-testing/lib/shapely/topology.py
===================================================================
--- trunk/toolkits/basemap-testing/lib/shapely/topology.py	                        (rev 0)
+++ trunk/toolkits/basemap-testing/lib/shapely/topology.py	2007-11-12 16:51:08 UTC (rev 4225)
@@ -0,0 +1,62 @@
+"""
+Support for GEOS topological operations.
+"""
+
+from shapely.geos import TopologicalError
+
+
+class BinaryTopologicalOp(object):
+
+    """A callable non-data descriptor.
+
+    Wraps a GEOS function. The factory is a callable which wraps results in
+    the appropriate shapely geometry class.
+    """
+
+    fn = None
+    context = None
+    factory = None
+
+    def __init__(self, fn, factory):
+        self.fn = fn
+        self.factory = factory
+
+    def __get__(self, obj, objtype=None):
+        self.context = obj
+        return self
+
+    def __call__(self, other):
+        product = self.fn(self.context._geom, other._geom)
+        if not product:
+            # Check validity of geometries
+            if not self.context.is_valid:
+                raise TopologicalError, \
+                "The operation '%s' produced a null geometry. Likely cause is invalidity of the geometry %s" % (self.fn.__name__, repr(self.context))
+            elif not other.is_valid:
+                raise TopologicalError, \
+                "The operation '%s' produced a null geometry. Likely cause is invalidity of the 'other' geometry %s" % (self.fn.__name__, repr(other))
+
+        return self.factory(product)
+
+
+class UnaryTopologicalOp(object):
+
+    """A data descriptor.
+    
+    Wraps a GEOS function. The factory is a callable which wraps results in
+    the appropriate shapely geometry class.
+    """
+    
+    fn = None
+    factory = None
+
+    def __init__(self, fn, factory):
+        self.fn = fn
+        self.factory = factory
+
+    def __get__(self, obj, objtype=None):
+        return self.factory(self.fn(obj._geom))
+    
+    def __set__(self, obj, value=None):
+        raise AttributeError, "Attribute is read-only"
+

Added: trunk/toolkits/basemap-testing/lib/shapely/wkb.py
===================================================================
--- trunk/toolkits/basemap-testing/lib/shapely/wkb.py	                        (rev 0)
+++ trunk/toolkits/basemap-testing/lib/shapely/wkb.py	2007-11-12 16:51:08 UTC (rev 4225)
@@ -0,0 +1,35 @@
+"""
+Load/dump geometries using the well-known binary (WKB) format.
+"""
+
+from ctypes import byref, c_int, c_size_t, c_char_p, string_at
+
+from shapely.geos import lgeos, ReadingError
+from shapely.geometry.base import geom_factory
+
+
+# Pickle-like convenience functions
+
+def loads(data):
+    """Load a geometry from a WKB string."""
+    geom = lgeos.GEOSGeomFromWKB_buf(c_char_p(data), c_size_t(len(data)));
+    if not geom:
+        raise ReadingError, \
+        "Could not create geometry because of errors while reading input."
+    return geom_factory(geom)
+
+def load(fp):
+    """Load a geometry from an open file."""
+    data = fp.read()
+    return loads(data)
+
+def dumps(ob):
+    """Dump a WKB representation of a geometry to a byte string."""
+    size = c_int()
+    bytes = lgeos.GEOSGeomToWKB_buf(ob._geom, byref(size))
+    return string_at(bytes, size.value)
+
+def dump(ob, fp):
+    """Dump a geometry to an open file."""
+    fp.write(dumps(ob))
+

Added: trunk/toolkits/basemap-testing/lib/shapely/wkt.py
===================================================================
--- trunk/toolkits/basemap-testing/lib/shapely/wkt.py	                        (rev 0)
+++ trunk/toolkits/basemap-testing/lib/shapely/wkt.py	2007-11-12 16:51:08 UTC (rev 4225)
@@ -0,0 +1,33 @@
+"""
+Load/dump geometries using the well-known text (WKT) format.
+"""
+
+from ctypes import byref, c_int, c_size_t, c_char_p, string_at
+
+from shapely.geos import lgeos, ReadingError
+from shapely.geometry.base import geom_factory
+
+
+# Pickle-like convenience functions
+
+def loads(data):
+    """Load a geometry from a WKT string."""
+    geom = lgeos.GEOSGeomFromWKT(c_char_p(data))
+    if not geom:
+        raise ReadingError, \
+        "Could not create geometry because of errors while reading input."
+    return geom_factory(geom)
+
+def load(fp):
+    """Load a geometry from an open file."""
+    data = fp.read()
+    return loads(data)
+
+def dumps(ob):
+    """Dump a WKB representation of a geometry to a byte string."""
+    return string_at(lgeos.GEOSGeomToWKT(ob._geom))
+
+def dump(ob, fp):
+    """Dump a geometry to an open file."""
+    fp.write(dumps(ob))
+


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