def along(line, distance, units):
if line["type"] == 'Feature':
coords = line["geometry"]["coordinates"]
elif line["type"] == 'LineString':
coords = line["coordinates"]
else:
raise ValueError("input must be a LineString Feature or Geometry")
travelled = 0
for i in range(len(coords)):
if distance >= travelled and (i == len(coords) - 1):
break
elif travelled >= distance:
overshot = distance - travelled
if not overshot:
return Point(coords[i])
else:
direction = bearing(coords[i], coords[i - 1]) - 180
interpolated = destination(coords[i], overshot, direction,
units)
return interpolated
else:
travelled += measure_distance(coords[i], coords[i + 1], units)
return Point(coords[coords.length - 1])
def inner_function(pt, coords, units):
closest_pt = Point((float("inf"), float("inf")), {
"dist": float("inf")
})
for i in range(len(coords)):
start = Point(coords[i])
stop = Point(coords[i + 1])
# start
start.properties.dist = distance(pt, start, units)
# stop
stop.properties.dist = distance(pt, stop, units)
# perpendicular
height_distance = max(start.properties.dist, stop.properties.dist)
direction = bearing(start, stop)
perpendicular_pt1 = destination(pt, height_distance, direction + 90, units)
perpendicular_pt2 = destination(pt, height_distance, direction - 90, units)
intersect = line_intersects(
perpendicular_pt1.geometry.coordinates[0],
perpendicular_pt1.geometry.coordinates[1],
perpendicular_pt2.geometry.coordinates[0],
perpendicular_pt2.geometry.coordinates[1],
start.geometry.coordinates[0],
start.geometry.coordinates[1],
stop.geometry.coordinates[0],
stop.geometry.coordinates[1]
)
if intersect:
intersect_pt = Point(intersect)
intersect_pt.properties.dist = distance(pt, intersect_pt, units)
if start.properties.dist < closest_pt.properties.dist:
closest_pt = start
closest_pt.properties.index = i
if stop.properties.dist < closest_pt.properties.dist:
closest_pt = stop
closest_pt.properties.index = i
if intersect_pt and intersect_pt.properties.dist < closest_pt.properties.dist:
closest_pt = intersect_pt
closest_pt.properties.index = i
return closest_pt
def circle(center, radius, steps, units):
steps = steps or 64
coordinates = []
for i in range(steps):
point = destination(center, radius, i * 360 / steps, units)
coordinates.append(point["geometry"]["coordinates"])
coordinates.append(coordinates[0])
return Polygon([coordinates])
def line_slice_along(line, start_dist, stop_dist, units):
slice = []
if line["type"] == 'Feature':
coords = line.geometry.coordinates
elif line["type"] == 'LineString':
coords = line.coordinates
else:
raise ValueError('input must be a LineString Feature or Geometry')
travelled = 0
for i in range(len(coords)):
if start_dist >= travelled and i == coords.length - 1:
break
elif travelled > start_dist and len(slice) == 0:
overshot = start_dist - travelled
if not overshot:
return slice.append(coords[i])
direction = bearing(coords[i], coords[i - 1]) - 180
interpolated = destination(coords[i], overshot, direction, units)
slice.append(interpolated.geometry.coordinates)
if travelled >= stop_dist:
overshot = stop_dist - travelled
if not overshot:
return slice.append(coords[i])
direction = bearing(coords[i], coords[i - 1]) - 180
interpolated = destination(coords[i], overshot, direction, units)
slice.append(interpolated.geometry.coordinates)
return LineString(tuple(slice))
if travelled >= start_dist:
slice.append(coords[i])
travelled += distance(coords[i], coords[i + 1], units)
return LineString(coords[coords.length - 1])
def midpoint(point_from, point_to):
dist = distance(point_from, point_to, 'miles')
heading = bearing(point_from, point_to)
return destination(point_from, dist / 2, heading, 'miles')