Geometry & space
The shapes themselves, where they sit on the earth, and how they relate.
Topics in Geometry & space
4 topics, 127 guides. Each topic page groups the concepts, the how-to guides and the fixes for that subject.
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Geometry & topology
Clipping, buffering, dissolving and overlays — and what makes a geometry valid.
13 concepts · 28 how-to · 9 fixes → -
CRS & projections
Coordinate systems, EPSG codes, reprojection, and the silent errors they cause.
7 concepts · 10 how-to · 14 fixes → -
Joins & relationships
Spatial joins, attribute joins, nearest neighbour and point-in-polygon.
7 concepts · 20 how-to · 6 fixes → -
Networks & routing
Street networks as graphs: shortest paths, travel time, isochrones and snapping.
3 concepts · 6 how-to · 4 fixes →
Every guide in Geometry & space
Grouped by topic. A guide that spans two topics appears under both.
Geometry & topology 50 guides
- How to Filter Spatial Data in Python Using GeoPandas filter geopandas data
- How to Clip Spatial Data in Python with GeoPandas clip shapefile python geopandas
- How to Dissolve Polygons in Python (GeoPandas) dissolve polygons geopandas
- How to Calculate Area and Distance in GeoPandas (Correctly) calculate area geopandas
- How to Create Buffers in GeoPandas for Spatial Analysis buffer analysis geopandas
- Overlay Operations in GeoPandas: Union, Intersection, Difference Explained geopandas overlay operations
- Shapely Basics: Working with Geometry Objects in Python shapely python geometry
- How to Get Polygon Centroids in GeoPandas polygon centroid geopandas
- How to Count Points in Polygons with GeoPandas count points in polygon geopandas
- How to Simplify Geometry in Python with GeoPandas and Shapely simplify geometry geopandas
- How to Create a Fishnet Grid in Python with GeoPandas fishnet grid python geopandas
- How to Convert a Raster to a Vector in Python raster to vector python
- How to Convert Points to Lines in GeoPandas points to line geopandas
- How to Aggregate Spatial Data by Region in GeoPandas aggregate spatial data geopandas
- How to Remove Null and Empty Geometries in GeoPandas remove null geometries geopandas
- How to Fix Invalid Geometries in Python (GeoPandas) invalid geometries geopandas
- Shapely TopologyException: Found Non-Noded Intersection (How to Fix) shapely topologyexception
- GeoPandas "No Geometry Column" Error: How to Fix It geopandas no geometry column
- How to Find and Remove Duplicate Geometries in GeoPandas remove duplicate geometries geopandas
- How to Snap and Align Geometries to Fix Slivers and Gaps in Python snap geometries fix slivers python
- How to Batch Clip Many Layers to a Single Boundary in Python batch clip shapefiles boundary python geopandas
- buffer(0) Does Not Fix My Invalid Geometry: What to Do Instead buffer 0 not fixing geometry
- Mixed Geometry Types Error When Saving a GeoDataFrame: How to Fix It mixed geometry types geopandas
- How to Split Multipart Geometries into Single Parts in GeoPandas explode multipart geometries geopandas
- What Makes a Geometry Valid? The OGC Rules Explained valid geometry rules gis
- WKT, WKB and GeoJSON: How Geometry Is Actually Stored wkt wkb geojson difference
- Topology in GIS Explained: Slivers, Gaps and Shared Boundaries gis topology explained
- Coordinate Precision and Floating Point in GIS Explained coordinate precision gis floating point
- Spatial Predicates Explained: Intersects, Within, Contains and the Rest spatial predicates geopandas
- Null, Empty, Missing and Invalid: Four Kinds of Broken Geometry empty geometry geopandas
- Topological Coverage: What "Clean" Means for Adjacent Polygons polygon coverage gaps overlaps
- How to Find and Fix Gaps and Overlaps in a Polygon Coverage fix gaps overlaps polygons python
- How to Clean a Line Network: Dangles, Overshoots and Disconnects clean road network topology python
- My Cleaned Layer Has More Rows Than the Original: How to Fix It geopandas more rows after cleaning
- How to Clip a Raster to a Polygon in Python clip raster to polygon python
- How to Rasterize a Vector Layer in Python rasterize vector python
- How to Add Legends, Labels and a Scale Bar to a GeoPandas Map geopandas map legend labels
- How to Plot Multiple Layers on One Map in GeoPandas plot multiple layers geopandas
- How to Assert on Geometry in pytest Without Flaky Comparisons pytest assert geometry equal
- Why GeoPandas Is Slow: The Four Real Bottlenecks why is geopandas slow
- How to Replace a Row Loop with Vectorised GeoPandas Operations vectorise geopandas loop
- GeoPandas .apply() Takes Hours: How to Fix It geopandas apply slow
- Projected vs Geographic CRS: What Actually Changes When You Reproject projected vs geographic crs
- How to Choose the Right Projected CRS for Your Study Area choose projected crs python
- How to Measure Distance Accurately in Python: Geodesic vs Projected measure distance accurately python
- Contours Come Out Jagged or Full of Tiny Rings contours jagged noisy
- Street Networks as Graphs Explained street network graph explained
- How to Calculate the Shortest Path Along a Street Network shortest path street network python
- NetworkX Says No Path Exists Between Two Nodes networkx no path exists
- Generalisation for Zoom Levels Explained zoom generalisation explained
CRS & projections 31 guides
- How to Calculate Area and Distance in GeoPandas (Correctly) calculate area geopandas
- EPSG Codes Explained: How to Choose the Right CRS in Python epsg codes python gis
- Spatial Join Returns Empty Results in GeoPandas: How to Fix It spatial join empty geopandas
- CRS Not Found Error in GeoPandas: Causes and Fixes crs not found geopandas
- Why Does My GeoPandas Map Look Upside Down? geopandas map upside down
- Coordinate Reference Systems (CRS) Explained for Python GIS coordinate reference systems python
- How to Reproject Spatial Data in Python (GeoPandas) reproject spatial data geopandas
- How to Fix CRS Mismatch in GeoPandas crs mismatch geopandas
- GeoPandas "Geometry Is in a Geographic CRS" Warning: How to Fix It geopandas geographic crs warning
- Cannot Transform Naive Geometries to CRS: How to Fix It in GeoPandas cannot transform naive geometries
- How to Standardise and Repair CRS Across a Folder of Files in Python standardise crs across files python
- My Points Plot in the Ocean: Fixing Swapped Latitude and Longitude points plotting in the ocean geopandas
- Coordinate Precision and Floating Point in GIS Explained coordinate precision gis floating point
- PostGIS Write Fails on SRID or Geometry Type: How to Fix It postgis srid does not match column
- Raster Resampling Explained: Nearest, Bilinear and When Each Is Wrong raster resampling methods
- How to Reproject a Raster in Python with Rasterio reproject raster rasterio
- Raster and Vector Do Not Line Up in Python: How to Fix It raster vector not aligned python
- Choosing a Map Projection for Display: What Web Mercator Distorts map projection for display python
- How to Add a Basemap to a GeoPandas Map with contextily geopandas basemap contextily
- My Folium Map Is Blank or Will Not Display: How to Fix It folium map not showing
- Projected vs Geographic CRS: What Actually Changes When You Reproject projected vs geographic crs
- How to Choose the Right Projected CRS for Your Study Area choose projected crs python
- How to Set, Assign and Convert CRS in GeoPandas (set_crs vs to_crs) set_crs vs to_crs geopandas
- How to Measure Distance Accurately in Python: Geodesic vs Projected measure distance accurately python
- How to Work with a Custom or Local CRS in Python custom crs proj string python
- How to Reproject Between Datums Correctly (and Why the Grid File Matters) datum transformation python pyproj
- Vertical Datums Explained: Why Your Elevations Are Off vertical datum explained
- Slope Values Are Wrong or Absurdly Steep slope values wrong
- Street Network Routing Returns Absurd Distances routing wrong distance
- laspy Returns the Wrong Coordinates: Scale, Offset and CRS laspy wrong coordinates
- My Tiles Are Offset or in the Wrong Place tiles are offset or misplaced
Joins & relationships 33 guides
- How to Filter Spatial Data in Python Using GeoPandas filter geopandas data
- How to Join Attribute Data to a GeoDataFrame in Python join attribute data geopandas
- How to Count Points in Polygons with GeoPandas count points in polygon geopandas
- How to Find the Nearest Point in GeoPandas nearest point geopandas
- How to Aggregate Spatial Data by Region in GeoPandas aggregate spatial data geopandas
- How to Select Features by Location in GeoPandas select by location geopandas
- Spatial Join Returns Empty Results in GeoPandas: How to Fix It spatial join empty geopandas
- How to Perform a Spatial Join in Python (GeoPandas) spatial join geopandas
- GeoPandas Merge Returns NaN or No Matches: How to Fix It geopandas merge no matches
- GeoPandas "Columns Overlap but No Suffix Specified" Error: How to Fix It columns overlap but no suffix specified
- GeoPandas Spatial Join Returns Duplicate Rows: How to Fix It geopandas spatial join duplicates
- How to Fuzzy-Match Place Names When Joining Spatial Data in Python fuzzy match place names python
- Spatial Indexes Explained: R-trees and Why Spatial Joins Are Fast spatial index r-tree explained
- How to Run Spatial SQL Queries from Python with PostGIS spatial sql query python postgis
- Spatial Predicates Explained: Intersects, Within, Contains and the Rest spatial predicates geopandas
- How to Merge Near-Duplicate Features in a Spatial Dataset merge near duplicate features python
- How to Enrich Many Files Against One Reference Layer batch spatial join reference layer
- How to Calculate Zonal Statistics in Python zonal statistics python
- How to Do a Spatial Join in PostGIS with SQL postgis spatial join sql
- How to Use the Spatial Index Directly in GeoPandas (sindex) geopandas sindex spatial index
- Spatial Join Cardinality Explained: One-to-One, One-to-Many and What to Do spatial join one to many
- Nearest-Neighbour Joins Explained: Distance, Ties and Search Radius nearest neighbour join explained
- Attribute Join or Spatial Join? Choosing How to Combine Two Layers attribute join vs spatial join
- How to Bin Points into Hexagons in Python hexbin points python
- Spatial Clustering Explained: DBSCAN, K-Means and What They Assume spatial clustering explained
- How to Cluster Points by Location with DBSCAN in Python dbscan spatial clustering python
- DBSCAN Returns One Giant Cluster or Labels Everything Noise dbscan one cluster
- How to Calculate Moran's I in Python morans i python
- Spatial Weights Warn About Islands or Moran's I Returns nan spatial weights islands warning
- Network Distance vs Straight-Line Distance Explained network distance vs straight line
- How to Snap Points to a Street Network in Python snap points to network python
- How to Aggregate Movement into Flows Between Zones aggregate movement flows python
- How to Interpolate to Polygons Instead of a Grid areal interpolation python
Networks & routing 13 guides
- OSMnx Download Fails, Hangs or Times Out osmnx timeout error
- Street Networks as Graphs Explained street network graph explained
- How to Build a Street Network Graph in Python with OSMnx street network graph python
- Your Street Network Graph Is Disconnected or Missing Streets osmnx graph disconnected
- Network Distance vs Straight-Line Distance Explained network distance vs straight line
- How to Snap Points to a Street Network in Python snap points to network python
- How to Calculate the Shortest Path Along a Street Network shortest path street network python
- NetworkX Says No Path Exists Between Two Nodes networkx no path exists
- Street Network Routing Returns Absurd Distances routing wrong distance
- How to Measure Network Distance for Many Origin-Destination Pairs network distance matrix python
- Isochrones Explained: Travel Time Areas and What They Assume isochrones explained
- How to Generate Isochrones in Python generate isochrones python
- How to Map-Match a GPS Track to a Street Network map match gps track python