# Tag Info

Accepted

### Welding individual line segments into one LineString using Shapely

You can use shapely's ops.linemerge to accomplish this: from shapely import geometry, ops # create three lines line_a = geometry.LineString([[0,0], [1,1]]) line_b = geometry.LineString([[1,1], [1,0]]...
• 1,724
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### Check if a point falls within a multipolygon with Python

Shapefiles have no type MultiPolygon (type = Polygon), but they support them anyway (all rings are stored in one feature = list of polygons, look at Converting huge multipolygon to polygons) The ...
• 55.2k

### Returning lat and long of centroid point with GeoPandas

Ran into this problem myself. If you want the x and y as separate GeoDataFrame columns, then this works nicely: gdf["x"] = gdf.centroid.map(lambda p: p.x) gdf["y"] = gdf.centroid.map(lambda p: p.y) ...
• 2,118

### Transforming Shapely Polygon and MultiPolygon objects

If you're using pyproj2, it's much easier to use a Transformer. Here's an example: import pyproj from shapely.ops import transform project = pyproj.Transformer.from_proj( pyproj.Proj(init='epsg:...
• 423
Accepted

### Removing small holes from the polygon

You can use the following example script. The script removes all holes from a polygon whose area is smaller than eps. from shapely import wkt from shapely.geometry import Polygon # sample polygon ...
• 77.3k
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### Returning percentage of area of polygon intersecting another polygon using shapely

Next code: import fiona from shapely.geometry import shape path1 = '/home/zeito/pyqgis_data/polygon1.shp' path2 = '/home/zeito/pyqgis_data/polygon8.shp' polygon1 = fiona.open(path1) polygon8 = ...
• 30.1k

### Make shapefile from raster-bounds in Python

With shapely box and GeoPandas import rasterio as rio ra = rio.open("raster.tif") bounds = ra.bounds Convert bounds to shapely geometry from shapely.geometry import box geom = box(*bounds) print(...
• 55.2k
Accepted

### Converting Polygon to MultiPolygon with Shapely?

You can wrap the polygon in a list and pass that as an argument to the MultiPolygon constructor. Demo: from shapely.geometry.multipolygon import MultiPolygon from shapely import wkt p = wkt.loads(u'...
• 1,709
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### Looking for GeoPandas QGIS equivalent of ArcGIS "Select by location" tool

If poly is a GeoDataFrame with a single geometry, extract this: polygon = poly.geometry[0] Then, you can use the within method to check which points are within the polygon: points.within(polygon) ...
• 3,933
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### Shapely coordinate sequence to GeoDataFrame

Make a shapely polygon geometry from coordinate pairs. Pass the polygon to GeoDataFrame constructor as a list. import geopandas as gpd from shapely.geometry import Polygon coords = [(151....
• 77.3k

### Getting polygon breadth in Shapely

# create example polygon poly = Polygon([(0, 0), (4, 0), (5, 2), (7, 5), (3, 2), (1, 3)]) # get minimum bounding box around polygon box = poly.minimum_rotated_rectangle # get coordinates of polygon ...
• 548
Accepted

### Turning GeoDataFrame of x,y coordinates into Linestrings using GROUPBY?

I think I found an interim solution, which I'm posting in case it's useful for anyone: import pandas as pd import numpy as np from geopandas import GeoDataFrame from shapely.geometry import Point, ...
• 1,549
Accepted

### Calculate distance from a Point within a Polygon to its edge

Compare the point to the polygon's exterior ring: poly.exterior.distance(point)
• 9,066
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### Plotting Shapely Multipolygon using Matplotlib

Shapely Polygon object has attribute exterior. Shapely MultiPolygon object has Polygon object sequence. You should iterate over those polygons. You can do that using attribute geoms of MultiPolygon. ...
• 77.3k

### Split lines at points using Shapely

You have many solutions and I use here a simple example 1) the easiest way from shapely.geometry import Point, LineString line = LineString([(1,2),(2,4),(4,5)]) point = Point(2,4) First, you must ...
• 55.2k
Accepted

### Intersecting two shape problem using geopandas

1) The problem is that the intersection of two polygons is not always a polygon import geopandas as gp poly1 = gp.read_file("poly_origin.shp") poly2 = gp.read_file("poly_test.shp") data = [] for ...
• 55.2k
Accepted

### Auto-select suitable UTM Zone based on Grid Intersection

There's the utm package, a bidirectional UTM-WGS84 converter for python. It's able to convert a (latitude, longitude) tuple into an UTM coordinate: import utm utm.from_latlon(51.2, 7.5) >>> (...
• 14.4k

### Rounding all coordinates in shapely

There are a few instances where @gene's answer does not work. For example, the using the overprecise value -73.92391000000001 geojson = {'type': 'Polygon', 'coordinates': [[[-73.92391, 41.31064], [-...
• 646
Accepted

### Drawing ellipse with shapely

Answer First, define a circle of radius 1. Then define an ellipse along x and y axis. Rotate the ellipse. Finally, actually draw the ellipse. Code from matplotlib import pyplot from shapely.geometry....
• 10.5k

### Auto-select suitable UTM Zone based on Grid Intersection

Alright, the answer from Antonio above is definitely right and pointed me in the correct direction. Here is the complete code: # convert_wgs_to_utm function, see https://stackoverflow.com/a/40140326/...
• 714
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### Geopandas Line Polygon Intersection

When comparing geodataframes with geometry operations in Geopandas, the geometries are first matched by index. In the case where there is no matching index (because you only have a single polygon for ...
• 15.7k
Accepted

### Shapely polygon union results in strange artifacts of tiny, non-overlapping areas

This is typically a result of the the borders not fitting perfectly one next to another (and this is very easy to get with floating point coordinates). As an example, I use the world dataset ...
• 3,933

### Snap points shapefile to line shapefile using shapely

The methodology is called linear referencing and a solution was given by Mike T in Coordinate of the closest point on a line with Shapely. There is also a recipe in the Python Geospatial Analysis ...
• 55.2k
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### Flipping coordinates with Shapely

You can use a simple transformation function with shapely.ops' transform function. For example: def flip(x, y): """Flips the x and y coordinate values""" return y,...
• 830

### What is unit of Shapely length attribute?

You can now use shapely w/ pyproj to get geodesic length in meters: From: https://pyproj4.github.io/pyproj/stable/api/geod.html#pyproj.Geod.geometry_length from pyproj import Geod from shapely....
• 826
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### Shapely - convert polygons to lines?

bugmenot123 is ok but I find easier use the boundary of the polygons. If you have a multipolygon or a polygon with holes the boundary returns a multilinestrig, if you have a polygon without holes the ...
• 2,460
Accepted

### How to extract biggest Polygon from MultiPolygon in GeoPandas?

Here's what I would do: max(multipolygon, key=lambda a: a.area) The built-in max function used this way will return the item from the list where lambda a: a.area is maximized.
• 915

### Is the LineString straight?

Maths should always work. You can basically test for the collinearity between the first vector of the line (i.e. composed by the two first points of the line) and all other vectors of the line (i.e. ...
• 10.5k

### Is the LineString straight?

A really simple way is to evaluate the sinuosity for each linestring, using something like this for shapely: def sinuosity(geom): assert geom.geom_type == "LineString", geom.geom_type ...
• 42.2k