def get_buffer(filename, lat, lon, radius):
"""
Given a geojson file, latitude and longitude in 4326 projection,
and a radius, write to file (as geojson) all the LineStrings and
Points that overlap a circular buffer around the coordinates.
Args:
filename
lat
lon
radius
Returns:
A list of overlapping geojson features 4326 projection
"""
segments = read_geojson(filename)
# Calculate the bounding circle
overlapping = []
point = get_reproject_point(lat, lon, transformer_4326_to_3857)
buffered_poly = point.buffer(radius)
for segment in segments:
if segment.geometry.intersects(buffered_poly):
if type(segment.geometry) == LineString:
coords = [x for x in segment.geometry.coords]
overlapping.append({
'geometry': {
'coordinates': coords,
'type': 'LineString'
},
'type': 'Feature',
'properties': segment.properties
})
elif type(segment.geometry) == Point:
overlapping.append({
'geometry': {
'coordinates':
[segment.geometry.x, segment.geometry.y],
'type': 'Point'
},
'properties': segment.properties
})
elif type(segment.geometry) == MultiLineString:
overlapping.append({
'geometry': {
'coordinates':
[[y for y in x.coords] for x in segment.geometry],
'type':
'MultiLineString'
},
'properties': segment.properties
})
else:
print("{} not implemented yet, skipping...".format(
type(segment.geometry)))
if overlapping:
overlapping = prepare_geojson(overlapping)
return overlapping
def test_get_buffer():
results = make_map_subset.get_buffer(
os.path.join(TEST_FP, 'data', 'test_make_map.geojson'), 42.3693239,
-71.10103649999999, 20)
assert len(results['features']) == 5
lines = [
x for x in results['features'] if x['geometry']['type'] == 'LineString'
]
assert len(lines) == 4
point = [
x for x in results['features'] if x['geometry']['type'] == 'Point'
]
assert len(point) == 1
# Make sure that all the resulting features are at least partially
# within the buffer
center_point = get_reproject_point(42.3693239, -71.10103649999999,
transformer_4326_to_3857)
buff_poly = center_point.buffer(20)
# To do this, have to convert the points and linestrings back to 3857
reprojected_lines = reproject_records(lines)
for r in reprojected_lines:
assert r['geometry'].intersects(buff_poly)
point_3857 = get_reproject_point(point[0]['geometry']['coordinates'][1],
point[0]['geometry']['coordinates'][0],
transformer_4326_to_3857)
assert point_3857.within(buff_poly)
results = make_map_subset.get_buffer(
os.path.join(TEST_FP, 'data', 'test_make_map.geojson'), 42.3601,
71.0589, 20)
assert results == []
# Test multilinestring
results = make_map_subset.get_buffer(
os.path.join(TEST_FP, 'data', 'make_map_multilinestring.geojson'),
42.3693167036633, -71.1010048225989, 20)
assert len(results['features']) == 1
def get_waze_buffer(filename, outfile, lat, lon, radius):
"""
Get waze elements that fall within a certain area
Write them back out to a json file
"""
items = json.load(open(filename))
items = [get_linestring(x) for x in items]
items = reproject_records(items)
point = get_reproject_point(lat, lon)
buffered_poly = point.buffer(radius)
count = 0
results = []
for item in items:
if item['geometry'].intersects(buffered_poly):
count += 1
results.append(item['properties'])
print("{} results found".format(count))
with open(outfile, 'w') as f:
json.dump(results, f)