Questions tagged [shapely]
Shapely is an open source Python package for construction and analysis of 2D planar geometric objects common to geographic information systems.
151
questions with no upvoted or accepted answers
8
votes
0answers
718 views
Shapely with Rtree versus STRtree
I have a huge interrogation regarding the performance difference between Rtree and STRtree included in Shapely. Below is a short code where we create randomly 250 000 triangles (defined by 4 vertice) ...
6
votes
0answers
107 views
“Merging” 2 layers of LineString with splits at intersections
I would like to "merge" 2 networks of lines and these lines need to be split when they intersect. With pictures it should be clearer :
What to do:
if a black line intersects a red line, they should ...
5
votes
0answers
387 views
Making polygon for every point in set using voronois?
I'm trying to make polygons from points, were each point will be represented by one polygon. I tried using voronois, but the results are incomplete. While I more or less understand where this ...
4
votes
0answers
50 views
Convert the geometry column of a GeoDataFrame with mixed geometry types to a unique multi-type
I have a GeoDataFrame where I have a mix of geometry types in its geometry column, some are multi-geometry types, some are single geometry types, some are empty geometry types, and others are None (...
4
votes
1answer
55 views
Obtaining a transform for Affine transformation (Cartesian to geodetic coordinate system)
I have a Line, defined as 2 points in a Cartesian coordinate system.
Shapely allows projecting this line with an affine transformation if a transform is specified.
from shapely.geometry import ...
4
votes
0answers
134 views
Performance improvement methods in a shapely environment
I am trying to use the Shapely and Fiona libraries to eliminate polygons from one layer (some triangles) from another layer (which represents the world's oceans).
I am looking for suggestions to ...
4
votes
0answers
4k views
Point in Polygon using Rtree and Shapely
I am wondering what the correct syntax is for doing a point in polygon search using Shapely and RTree. I'm really interested in speeding the process up using the RTree index but am not having any luck ...
4
votes
1answer
1k views
Using shapely.affinity and affine_transform?
I have shapely.geometry Point:
from shapely.geometry import Point
point1 = Point(0, 100, 200)
and I want to swap coordinates Y and Z:
from shapely.affinity import affine_transform
matrix = [1,0,0, ...
3
votes
0answers
22 views
Calculating population within a circle excluding intersects with shapely
I have a data of a centroid and a count:
centroid population id
0 POINT(38.9081 77.0349) 9004.0 0
1 POINT(38.8521,77.0377) 517.0 1
2 POINT(38.9081 77.0377) 10369.0 ...
3
votes
3answers
126 views
Finding all possible adjacent/closest geometrical points from a given point
So, I have a dataframe like this,
import numpy as np
import pandas as pd
import descartes
from shapely.geometry import Point, Polygon
import geopandas as gpd
import matplotlib.pyplot as plt
df = pd....
3
votes
0answers
128 views
GEOS segmentation fault when loading libc.so.6
I'm trying to run a program that uses shapely on a GCE Virtual Machine (Ubuntu 18.04). I'm getting an error on the geos.py file, here is the relevant trace I'm getting:
[geos:73] - [DEBUG]: Found ...
3
votes
0answers
86 views
Assign area of polygon to raster cell. Effective way in Python
I have quite interesting task to resolve, but my solution is not effective, so I am looking for some advice to improve my code. I have raster dataset covering Europe, in crs WGS 1984 (4326). The cells ...
3
votes
0answers
492 views
Multi-part geometries do not themselves provide the array interface
So initially I had multiple perpendicular lines along a coastline.
Next I clipped these lines based on polygons along the coastline,such as the follwing.
I am trying to use this resulting shapefile ...
3
votes
1answer
294 views
Find the closest line to a polygon Python Rtree
I have a series of fields and roads I am trying to find the nearest road to each field. I want to add field to each of my polygons with the index/name/etc of the closest road.
Would this be the ...
3
votes
0answers
76 views
Split line at regular intervals in shapely
I have been trying to use Shapely to split a shapefile with multiple features at regular intervals. I have used the split function to do this. I can easily create the points at which the lines should ...
3
votes
0answers
219 views
Find a centerline of an intersection between two irregular shaped polygons
I have two irregular shaped polygons that overlap each other at least in at two points. I want to first find the intersection area between all of them, then for the polygon pair that intersects I want ...
3
votes
0answers
75 views
Shapefile polygon operation efficiency
I would like to make a graph from a shapefile, where edges would express spatial relations between polygons according to DE-9IM
For that, I use fiona + shapely
My code is working but it is extremely ...
3
votes
0answers
152 views
Merge linestrings between two nodes based on condition
I am working with dense openstreetmap road networks and I am trying to simplify the network. To simplify it, I would like to merge all the linestrings that only intersect with one other line, as shown ...
3
votes
0answers
435 views
Alpha hull with island
I need the 'concave hull' or alphashape of a set of points. Also, I'd like to have it with holes/donuts/islands in the middle. See my attached image. The outer hull is being calculated fine. But the ...
3
votes
0answers
830 views
Install shapely for QGIS on Mac
I know there are a number of similar questions, but none of them have answers that allow me to use shapely in QGIS. In particular I am trying to install the Contour plugin, but this fails with the ...
3
votes
0answers
893 views
Importing matplotlib basemap and shapely
I'm not sure if this is the right place to ask this, but here we go.
I have a python script that uses matplotlib's basemap and another part that uses shapely to do an intersection of 2 polygons. If ...
2
votes
1answer
268 views
Find nearest polygon (from GeoSeries) to point (from GeoSeries)
I have two GeoSeries, consisting of points and polygons. I want to find the polygon in dataframe B that is closest to each point in dataframe A. The polygons are rooftops from https://github.com/...
2
votes
0answers
241 views
Failure to write LineString record to shapefile
I have some coordinates from which I am creating a shapefile.
tafo_boundary_coords = [(652316, 742792), (652161, 742920), (651897, 743166), (652210, 743477), (652298, 743448),(652375, 743458), (...
2
votes
0answers
40 views
How to cluster interconnected lines in Python without PostGIS?
I'm working with a subset of data from OpenStreetMap, where I have these island-like groups of line features. The groups are not connected to one another, but the lines are all interconnected within ...
2
votes
0answers
77 views
Geopandas shows points outside of buffer geometry even though inside
I have some ship trajectories and I want to know which point of the trajectory is inside the port(=buffer) and which points are outside. The following picture shows my Geopandas Dataframe with the ...
2
votes
0answers
51 views
Polygonize every single pixel of a raster
How can I get every pixel separated? When I calc unique values, if two pixels have the same value, it converts in one row in the final shape. I need every single pixel converted into one unique ...
2
votes
0answers
151 views
More stable spatial sort using Shapely's within?
I was trying to use a modified version of the spatial sorting method illustrated in shapely's documentation, using only polygons exteriors (so that I can detect if a polygon lies inside another ...
2
votes
0answers
64 views
Problem when trying to cut linestring at multiple points after conversion from Multi-linestring
This is my script:
def cut_line_at_points(line, points):
'''
line is gdf format
points are series of points in gdf format
'''
# union all geometries - convert the gdf to shpely (...
2
votes
0answers
55 views
ESRI Geometry Union slower than Built in dissolve which is slower than Shapely
I work with point datasets a lot. We try to keep a running layer of points and update the dataset with new points while removing the old points. So, we do a lot of checking the extents of the new ...
2
votes
0answers
468 views
CRS of Shapely Object
I've imported a row from a Postgres DB using sqlalchemy.
One of the column types is GEOMETRY from postgis and upon import
>>>> type(row[0].geom)
returns
class 'geoalchemy2.elements....
2
votes
0answers
43 views
Creating Swath View from Point data using Python?
My situation
Input: point data from planting file
Feature Attribute:
[('DeletionFlag', 'C', 1, 0), ['Field', 'C', 254, 0], ['Dataset', 'C', 254, 0], ['Product', 'C', 254, 0], ['Obj__Id', 'N', 15,...
2
votes
1answer
714 views
Finding shortest distance from point(s) to number of polygons at varying angles using shapely?
My aim is to calculate the distance a point is from land in Python, trying to replicate the functionality of fetchR.
Given an origin and distance, I create shapely LineStrings which radiate out from ...
2
votes
0answers
2k views
Geopandas simplify results in gaps between polygons
The goal is to simplify the geometries of a shapefile containing multipolygons. However, when I use Shapely's simplify in geopandas, the result contains gaps between the polygons. I was hoping that ...
2
votes
0answers
467 views
Intersecting shapefile/GeoDataFrame using Geopandas, shapely etc?
I'm currently transferring from ESRI to open source GIS by recreating basic ArcGIS tasks in Python, mainly using Geopandas since I have some experience with Pandas.
Now I'm trying to intersect a ...
2
votes
0answers
210 views
Dissolve Line Strings to one string - “No Shapely geometry can be created from null value”
I have a layer with 7000 LineStrings, all represent bus routes:
It seems that all the bus routes are contiguous, but I'm not sure of it.
I'm trying to use python shapely to dissolve all those ...
2
votes
0answers
97 views
Cut line at intersection using Shapely
I'm trying to cut a line at the intersection, if a line crosses another line within a single multilinestring then and the end of the line is below a maximum distance threshold then it swaps the end of ...
2
votes
0answers
3k views
How to prevent “Type error: unhashable type” while writing properties with Fiona?
Using shapely's dissolve method I created new geometries from two existing shapefiles. Now I would like to save those new geometries and their properties with Fiona.
I have tried to write the ...
2
votes
0answers
275 views
Shapely .project() function not working on horizontal or vertical sections of line
I have a function called intersect_point_to_line that includes the following relevant code snippet:
for i in range(len(segment.coords[:])):
if i < len(segment.coords)-1:
seg = ...
2
votes
0answers
848 views
Generating a single geohash for a bounding box in python
the following code generates bounding box for the coordinates that are given in the input but currently it generates geohashes for all the 4 coordinates of the polygon. i want to be able to generate a ...
2
votes
0answers
579 views
No handlers could be found for logger “shapely.geos”
I have the following code to get area of polygon using shapely and pycrs.
I was able to run this code successfully in a jupyter notebook but when I incorporate it into my main code, I had an error ...
2
votes
0answers
218 views
Classify / section line or group of points according to shape (with shapely objects)
Is there any python module/function that classifies/sections a shapely line according to the shape the line forms?
If not, I could do it with the positions of the points that form the line. I would ...
2
votes
1answer
433 views
Storing Shapely polygons in MySQL
I have to store some polygons in a MySQL database. The polygons are in Plate Carrée (ESPG 32662) projection, but I also tried to first converting them to the usual latitude-longitude projection (ESPG ...
2
votes
1answer
480 views
When does Shapely's “polygonize_full” detect a dangle?
Shapely's polygonize_full operation, which merges line segments into polygons, returns four geometry collections: polygons, dangles, cuts and invalid ring lines. Dangles are defined in the ...
2
votes
0answers
756 views
Find Properties of Nearest Line Segments to Point in Python
I have been trying to find a workable Python approach to finding nearest line segments to one (or more) points, and came accross @gene's solution to @RustyMagoo's problem here:
from shapely.geometry ...
2
votes
0answers
588 views
How do I create a raster file from a geopandas dataframe storing lats, longs, values, and geometries
From a text file with time, lat, long, and cf values, I create a pandas dataframe (cf_df). Then I use the lat, long values to create a geoseries and create a geopandas dataframe from the original ...
2
votes
1answer
1k views
Interpolating every X distance along line in shapely
If I have a shapely multiline object that contains many lines whose total length each is 50km (when traced from the origin), and I want to interpolate along the multiline every X meters (let's say ...
2
votes
0answers
569 views
Projecting GeoJSON polygon object in python to calculate area
I have a script, written in python, that does many calculations - but one set of calculations hinges on determining the area of a polygon that I read in, in GeoJSON format. I can convert this object ...
2
votes
0answers
106 views
Where is my Polygon?
I created this script to merge all of the polygons in a shapefile into a single polygon. I am using Python 2.7.5, Shapely 1.3.0, and Fiona 1.1.5.
def merge(path_in, path_out):
#Import Libraries
...
2
votes
0answers
740 views
Why does polygon.intersection(complex_linestring) split the linestring and mess up Z?
I have a complex (self crossing) line with Z values which I'd like to truncate to the area inside a box. The problem is Shapely splits the line into simple (non-crossing) sections and the Z value at ...
1
vote
0answers
32 views
Geopandas .difference between two different shapes produces empty difference
I have been puzzled by this, and I feel like it's a geopandas bug.
base = gpd.GeoSeries(dist_to_remove).plot(edgecolor='black', color='yellow')
gpd.GeoSeries(prec_shape).plot(ax = base, color='red', ...
