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54 votes
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How to polygonize raster to shapely polygons

Use rasterio of Sean Gillies. It can be easily combined with Fiona (read and write shapefiles) and shapely of the same author. In the script rasterio_polygonize.py the beginning is import rasterio ...
gene's user avatar
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39 votes
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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]]...
songololo's user avatar
  • 1,694
35 votes
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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 ...
gene's user avatar
  • 54.7k
33 votes

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) ...
Martin Valgur's user avatar
31 votes

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:...
Nick ODell's user avatar
26 votes

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(...
gene's user avatar
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25 votes
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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 = ...
xunilk's user avatar
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25 votes
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Removing small holes from the polygon

You can use the following example script. The script removes all holes from a polygon whose area is greater than eps. from shapely import wkt from shapely.geometry import Polygon # sample polygon ...
Kadir Şahbaz's user avatar
24 votes
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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'...
jpmc26's user avatar
  • 1,709
24 votes
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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) ...
joris's user avatar
  • 3,883
23 votes
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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....
Kadir Şahbaz's user avatar
20 votes
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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, ...
atkat12's user avatar
  • 1,549
20 votes
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Calculate distance from a Point within a Polygon to its edge

Compare the point to the polygon's exterior ring: poly.exterior.distance(point)
sgillies's user avatar
  • 9,036
20 votes
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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. ...
Kadir Şahbaz's user avatar
19 votes
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Converting Shapely MultiPolygon to Polygon: Technique doesn't always work

You need to understand the Shapely binary predicates: If the two polygons intersects the result of union or unary_union (in red) is a Polygon therefore you can computes the exterior If the two ...
gene's user avatar
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19 votes
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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 ...
gene's user avatar
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19 votes
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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) >>> (...
Antonio Falciano's user avatar
19 votes

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 ...
Vaiaro's user avatar
  • 528
18 votes
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Intersecting two shapefiles from Python or command line?

The question is about Shapely and Fiona in pure Python without QGIS ("using command line and/or shapely/fiona"). A solution is from shapely import shape, mapping import fiona # schema of the new ...
gene's user avatar
  • 54.7k
18 votes

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 ...
gene's user avatar
  • 54.7k
17 votes
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Rounding all coordinates in shapely?

Shapely and GEOS cannot reduce precision (floating-point precision problem) but you can use other functions as numpy.round() or round(),with the GeoJSON format. For polygons from shapely.geometry ...
gene's user avatar
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17 votes
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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....
swiss_knight's user avatar
  • 10.1k
16 votes

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], [-...
koshmaster's user avatar
15 votes
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Difference between Crosses & Intersects - Shapely (Python)

From Shapely's doc: intersects() is equivalent to the OR-ing of contains(), crosses(), equals(), touches(), and within(). So there might be some cases where two lines intersect eachother without ...
ArMoraer's user avatar
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15 votes
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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 ...
om_henners's user avatar
  • 15.6k
15 votes

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/...
Alex's user avatar
  • 704
15 votes
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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 ...
joris's user avatar
  • 3,883
15 votes

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 ...
gene's user avatar
  • 54.7k
15 votes
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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,...
inc42's user avatar
  • 820
14 votes
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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.
Paul H's user avatar
  • 915

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