def read_bathymetry_file():
log.info('Building irregular-grid index from bathymetry file. This will take awhile.')
then = datetime.now()
def take(k, source):
while k>0:
yield re.split(r'\s*', source.readline().strip())
k -= 1
src = open(settings.BATHYMETRY_SOURCE_FILE)
version = src.readline().strip()
num_edges, num_nodes = [int(k) for k in re.split(r'\s*', src.readline().strip())]
log.info("Reading {num_edges} triangles from {num_nodes} total nodes".format(num_edges=num_edges, num_nodes=num_nodes))
zvalues = np.empty(num_nodes+1, dtype=np.float_)
nodes_arr = np.empty((num_nodes+1, 2), dtype=np.float_)
triangle_arr = np.empty((num_edges+1, 3), dtype=np.int_)
triangle_coords_arr = np.empty((num_edges+1, 3, 2), dtype=np.float_)
#triangle_coords_arr = {}
for node, x, y, z in take(num_nodes, src):
node = int(node)
nodes_arr[node][0] = float(x)
nodes_arr[node][1] = float(y)
zvalues[node] = z
log.info('Built node array')
for triangle, dim, node1, node2, node3 in take(num_edges, src):
node1 = int(node1)
node2 = int(node2)
node3 = int(node3)
triangle = int(triangle)
triangle_arr[triangle][0] = node1
triangle_arr[triangle][1] = node2
triangle_arr[triangle][2] = node3
triangle_coords_arr[triangle][0] = nodes_arr[node1]
triangle_coords_arr[triangle][1] = nodes_arr[node2]
triangle_coords_arr[triangle][2] = nodes_arr[node3]
#triangle_coords_arr[triangle] = Polygon(( tuple(nodes_arr[node1]), tuple(nodes_arr[node2]), tuple(nodes_arr[node3]), tuple(nodes_arr[node1]) ), srid=4326)
log.info('Built triangle array')
obj = StaticArray.objects.filter(name='bathymetry', long_name='bathymetry').first() or StaticArray(name='bathymetry', long_name='bathymetry')
obj.data = pickle.dumps(zvalues)
obj.save()
log.info('Saved bathymetry data')
if os.path.exists(settings.BATHYMETRY_INDEX_FILE + '.idx'):
os.unlink(settings.BATHYMETRY_INDEX_FILE + '.idx')
os.unlink(settings.BATHYMETRY_INDEX_FILE + '.dat')
index = GeoIndex(settings.BATHYMETRY_INDEX_FILE, 'bathymetry', str, int, clear=True) # bulk load
cs = ((i, triangle_arr[i]) for i in range(1, triangle_arr.shape[0]))
triangles = ((i, Polygon(( tuple(nodes_arr[c1]), tuple(nodes_arr[c2]), tuple(nodes_arr[c3]), tuple(nodes_arr[c1]) ), srid=4326) ) for i, (c1, c2, c3) in cs)
index.bulk_insert(triangles)
log.info('saved geometry index')
np.save(settings.BATHYMETRY_INDEX_FILE + "bathymetry.nodes.npy", triangle_arr)
log.info('saved nodes')
np.save(settings.BATHYMETRY_INDEX_FILE + 'bathymetry.coords.npy', triangle_coords_arr)
log.info('saved coordinates')
index.close()
delta = datetime.now() - then
log.info('Finished building index in {secs} seconds.'.format(secs=delta.seconds))
