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from __future__ import print_function
import sys
import vtk
from vtk.test import Testing
def load_geojson(input_string, feature_properties={}):
'''Parses input_string with vtkGeoJSONReader, returns vtkPolyData
feature_properties is a dictionary of name-default_values
to attach as cell data in the returned vtkPolyData.
'''
reader = vtk.vtkGeoJSONReader()
#reader.DebugOn()
reader.StringInputModeOn()
reader.SetStringInput(input_string)
for name,default_value in feature_properties.items():
reader.AddFeatureProperty(name, default_value)
reader.Update()
return reader.GetOutput()
if __name__ == '__main__' :
# Use feature collection example taken from the geojson spec.
# Coped from http://geojson.org/geojson-spec.html (October 2014).
# Features are in/near the island of Summatra (in western Indonesia).
input_string = \
"""
{ "type": "FeatureCollection",
"features": [
{ "type": "Feature",
"geometry": {"type": "Point", "coordinates": [102.0, 0.5]},
"properties": {"prop0": "value0"}
},
{ "type": "Feature",
"geometry": {
"type": "LineString",
"coordinates": [
[102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0]
]
},
"properties": {
"prop0": "value0",
"prop1": 0.0
}
},
{ "type": "Feature",
"geometry": {
"type": "Polygon",
"coordinates": [
[ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0],
[100.0, 1.0], [100.0, 0.0] ]
]
},
"properties": {
"prop0": "value0",
"prop1": {"this": "that"}
}
}
]
}
"""
prop0_default = vtk.vtkVariant('default')
feature_properties = {'prop0': prop0_default}
polydata = load_geojson(input_string, feature_properties)
if polydata is None:
print('Failed to read input string and return vtkPolyData')
sys.exit(1)
num_errors = 0
# Check cell counts
expected_verts = 1
expected_lines = 1
expected_polys = 1
num_verts = polydata.GetNumberOfVerts()
if num_verts != expected_verts:
print('Wrong number of verts: returned %s, should be %s' % \
(num_verts, expected_verts))
num_errors += 1
num_lines = polydata.GetNumberOfLines()
if num_lines != expected_lines:
print('Wrong number of lines: returned %s, should be %s' % \
(num_lines, expected_lines))
num_errors += 1
else:
# Check number of points in the (first) polyline
id_list = vtk.vtkIdList()
polydata.GetLines().GetCell(0, id_list)
if id_list.GetNumberOfIds() != 4:
print('Wrong number of points in line 0: returned %s, should be %s' % \
(id_list.GetNumberOfIds(), 4))
num_errors += 1
num_polys = polydata.GetNumberOfPolys()
if num_polys != expected_polys:
print('Wrong number of polys: returned %s, should be %s' % \
(num_polys, expected_polys))
num_errors += 1
else:
# Check number of points in the (first) polygon
id_list = vtk.vtkIdList()
polydata.GetPolys().GetCell(0, id_list)
if id_list.GetNumberOfIds() != 4:
print('Wrong number of points in poly 0: returned %s, should be %s' % \
(id_list.GetNumberOfIds(), 4))
num_errors += 1
# Check cell data
cell_data = polydata.GetCellData()
# All polydata generated from GeoJSON have feature-id array
feature_id_array = cell_data.GetAbstractArray('feature-id')
if feature_id_array is None:
print('feature-id array missing')
num_errors += 1
# Test case also specified a prop0 array
prop0_array = cell_data.GetAbstractArray('prop0')
if prop0_array is None:
print('prop0 array missing')
num_errors += 1
print('num_errors:', num_errors)
sys.exit(num_errors)
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