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Linestring1 = LINESTRING (51.2176008 4.4177154, 51.21758 4.4178548, **51.2175729 4.4179023**, *51.21745162000732 4.41871738126533*)
Linestring2 = LINESTRING (*51.21745162000732 4.41871738126533*, **51.2174025 4.4190475**, 51.217338 4.4194807, 51.2172511 4.4200562, 51.2172411 4.4201077, 51.2172246 4.4201654, 51.2172067 4.420205, 51.2171806 4.4202355, 51.2171074 4.4202929, 51.2170063 4.4203409, 51.2169564 4.4203641, 51.2168076 4.4204243, 51.2166588 4.4204833, 51.2159018 4.420431, 51.2154117 4.4203843)
Considering these two linestrings were cut from a bigger linestring, how to get the endpoint of a LineString?
- Point(51.21745162000732 4.41871738126533) removed
- The new last element of linestring 1 = “ 51.2175729 4.4179023
- The new first element of linestring 2 = “ 51.2174025 4.4190475
In short, I want to get the new last value of the first part (linestring1) and the new first value of the second part (linestring2), but without the point where I cut them. How can I make this work?
633
To get endpoints of a LineString, you just need to access its boundary property: from shapely.geometry import LineString line = LineString ( [ (0, 0), (1, 1), (2, 2)]) endpoints = line.boundary print (endpoints) # MULTIPOINT (0 0, 2 2) first, last = line.boundary print (first, last) # POINT (0 0) POINT (2 2)
If have two points, from which I want to create a straight LineString object: from shapely.geometry import Point, LineString A = Point (0,0) B = Point (1,1) The Shapely manual for LineString states: A sequence of Point instances is not a valid constructor parameter. A LineString is described by points, but is not composed of Point instances.
The output point feature class will also have a field called LineOID, which records the OID of the polyline it was created from. That way you can join your attribute data back. In QGIS use Extract Specific Vertices tool. Set Vertex indices to 0 to get start points and -1 to get end points or 0,-1 to get both.
The nearest_points()function in shapely.opscalculates the nearest points in a pair of geometries. shapely.ops.nearest_points(geom1, geom2)¶ Returns a tuple of the nearest points in the input geometries.
To get endpoints of a LineString, you just need to access its boundary property:
from shapely.geometry import LineString
line = LineString([(0, 0), (1, 1), (2, 2)])
endpoints = line.boundary
print(endpoints)
# MULTIPOINT (0 0, 2 2)
first, last = line.boundary
print(first, last)
# POINT (0 0) POINT (2 2)
Alternatively, you can get the first and the last points from the coords cordinate sequence:
from shapely.geometry import Point
first = Point(line.coords[0])
last = Point(line.coords[-1])
print(first, last)
# POINT (0 0) POINT (2 2)
In your specific case, though, as you want to remove the last point of the first line, and the first point of the second line, and only after that get the endpoints, you should construct new LineString objects first using the same coords property:
from shapely.wkt import loads
first_line = loads("LINESTRING (51.2176008 4.4177154, 51.21758 4.4178548, 51.2175729 4.4179023, 51.21745162000732 4.41871738126533)")
second_line = loads("LINESTRING (51.21745162000732 4.41871738126533, 51.2174025 4.4190475, 51.217338 4.4194807, 51.2172511 4.4200562, 51.2172411 4.4201077, 51.2172246 4.4201654, 51.2172067 4.420205, 51.2171806 4.4202355, 51.2171074 4.4202929, 51.2170063 4.4203409, 51.2169564 4.4203641, 51.2168076 4.4204243, 51.2166588 4.4204833, 51.2159018 4.420431, 51.2154117 4.4203843)")
first_line = LineString(first_line.coords[:-1])
second_line = LineString(second_line.coords[1:])
print(first_line.boundary[1], second_line.boundary[0])
# POINT (51.2175729 4.4179023) POINT (51.2174025 4.4190475)
Similar to Georgy's solution, you can get their coords by unpacking the one you want and ignoring the rest using *_.
from shapely.geometry import LineString
linestring1 = LineString([(51.2176008, 4.4177154), (51.21758, 4.4178548),
(51.2175729, 4.4179023),
(51.21745162000732, 4.41871738126533)])
linestring2 = LineString([(51.21745162000732, 4.41871738126533),
(51.2174025, 4.4190475), (51.217338, 4.4194807),
(51.2172511, 4.4200562), (51.2172411, 4.4201077),
(51.2172246, 4.4201654), (51.2172067, 4.420205),
(51.2171806, 4.4202355), (51.2171074, 4.4202929),
(51.2170063, 4.4203409), (51.2169564, 4.4203641),
(51.2168076, 4.4204243), (51.2166588, 4.4204833),
(51.2159018, 4.420431), (51.2154117, 4.4203843)])
*_, last_new_1, last_1 = linestring1.coords
first_2, first_new_2, *_ = linestring2.coords
print(last_new_1)
print(first_new_2)
# (51.2175729, 4.4179023)
# (51.2174025, 4.4190475)
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