webapp/django/contrib/gis/gdal/prototypes/geom.py

from datetime import date
from ctypes import c_char, c_char_p, c_double, c_int, c_ubyte, c_void_p, POINTER
from django.contrib.gis.gdal.envelope import OGREnvelope
from django.contrib.gis.gdal.libgdal import lgdal, gdal_version
from django.contrib.gis.gdal.prototypes.errcheck import check_bool, check_envelope
from django.contrib.gis.gdal.prototypes.generation import \
    const_string_output, double_output, geom_output, int_output, \
    srs_output, string_output, void_output

# Some prototypes need to be aware of what version GDAL we have.
major, minor = map(int, gdal_version().split('.')[:2])
if major <= 1 and minor <= 4:
    GEOJSON = False
else:
    GEOJSON = True

### Generation routines specific to this module ###
def env_func(f, argtypes):
    "For getting OGREnvelopes."
    f.argtypes = argtypes
    f.restype = None
    f.errcheck = check_envelope
    return f

def pnt_func(f):
    "For accessing point information."
    return double_output(f, [c_void_p, c_int])

def topology_func(f):
    f.argtypes = [c_void_p, c_void_p]
    f.restype = c_int
    f.errchck = check_bool
    return f

### OGR_G ctypes function prototypes ###

# GeoJSON routines, if supported.
if GEOJSON:
    from_json = geom_output(lgdal.OGR_G_CreateGeometryFromJson, [c_char_p])
    to_json = string_output(lgdal.OGR_G_ExportToJson, [c_void_p], str_result=True)
else:
    from_json = False
    to_json = False

# GetX, GetY, GetZ all return doubles.
getx = pnt_func(lgdal.OGR_G_GetX)
gety = pnt_func(lgdal.OGR_G_GetY)
getz = pnt_func(lgdal.OGR_G_GetZ)
    
# Geometry creation routines.
from_wkb = geom_output(lgdal.OGR_G_CreateFromWkb, [c_char_p, c_void_p, POINTER(c_void_p), c_int], offset=-2)
from_wkt = geom_output(lgdal.OGR_G_CreateFromWkt, [POINTER(c_char_p), c_void_p, POINTER(c_void_p)], offset=-1)
create_geom = geom_output(lgdal.OGR_G_CreateGeometry, [c_int])
clone_geom = geom_output(lgdal.OGR_G_Clone, [c_void_p])
get_geom_ref = geom_output(lgdal.OGR_G_GetGeometryRef, [c_void_p, c_int])
get_boundary = geom_output(lgdal.OGR_G_GetBoundary, [c_void_p])
geom_convex_hull = geom_output(lgdal.OGR_G_ConvexHull, [c_void_p])
geom_diff = geom_output(lgdal.OGR_G_Difference, [c_void_p, c_void_p])
geom_intersection = geom_output(lgdal.OGR_G_Intersection, [c_void_p, c_void_p])
geom_sym_diff = geom_output(lgdal.OGR_G_SymmetricDifference, [c_void_p, c_void_p])
geom_union = geom_output(lgdal.OGR_G_Union, [c_void_p, c_void_p])

# Geometry modification routines.
add_geom = void_output(lgdal.OGR_G_AddGeometry, [c_void_p, c_void_p])
import_wkt = void_output(lgdal.OGR_G_ImportFromWkt, [c_void_p, POINTER(c_char_p)])

# Destroys a geometry
destroy_geom = void_output(lgdal.OGR_G_DestroyGeometry, [c_void_p], errcheck=False)

# Geometry export routines.
to_wkb = void_output(lgdal.OGR_G_ExportToWkb, None, errcheck=True) # special handling for WKB.
to_wkt = string_output(lgdal.OGR_G_ExportToWkt, [c_void_p, POINTER(c_char_p)])
to_gml = string_output(lgdal.OGR_G_ExportToGML, [c_void_p], str_result=True)
get_wkbsize = int_output(lgdal.OGR_G_WkbSize, [c_void_p])

# Geometry spatial-reference related routines.
assign_srs = void_output(lgdal.OGR_G_AssignSpatialReference, [c_void_p, c_void_p], errcheck=False)
get_geom_srs = srs_output(lgdal.OGR_G_GetSpatialReference, [c_void_p])

# Geometry properties
get_area = double_output(lgdal.OGR_G_GetArea, [c_void_p])
get_centroid = void_output(lgdal.OGR_G_Centroid, [c_void_p, c_void_p])
get_dims = int_output(lgdal.OGR_G_GetDimension, [c_void_p])
get_coord_dims = int_output(lgdal.OGR_G_GetCoordinateDimension, [c_void_p])

get_geom_count = int_output(lgdal.OGR_G_GetGeometryCount, [c_void_p])
get_geom_name = const_string_output(lgdal.OGR_G_GetGeometryName, [c_void_p])
get_geom_type = int_output(lgdal.OGR_G_GetGeometryType, [c_void_p])
get_point_count = int_output(lgdal.OGR_G_GetPointCount, [c_void_p])
get_point = void_output(lgdal.OGR_G_GetPoint, [c_void_p, c_int, POINTER(c_double), POINTER(c_double), POINTER(c_double)], errcheck=False)
geom_close_rings = void_output(lgdal.OGR_G_CloseRings, [c_void_p], errcheck=False)

# Topology routines.
ogr_contains = topology_func(lgdal.OGR_G_Contains)
ogr_crosses = topology_func(lgdal.OGR_G_Crosses)
ogr_disjoint = topology_func(lgdal.OGR_G_Disjoint)
ogr_equals = topology_func(lgdal.OGR_G_Equals)
ogr_intersects = topology_func(lgdal.OGR_G_Intersects)
ogr_overlaps = topology_func(lgdal.OGR_G_Overlaps)
ogr_touches = topology_func(lgdal.OGR_G_Touches)
ogr_within = topology_func(lgdal.OGR_G_Within)

# Transformation routines.
geom_transform = void_output(lgdal.OGR_G_Transform, [c_void_p, c_void_p])
geom_transform_to = void_output(lgdal.OGR_G_TransformTo, [c_void_p, c_void_p])

# For retrieving the envelope of the geometry.
get_envelope = env_func(lgdal.OGR_G_GetEnvelope, [c_void_p, POINTER(OGREnvelope)])