Skip to content
Kharita Challenges

Problems

Real geospatial problems, graded automatically. Choose a track, a level and what you want to hand in.

1 of 59 problems

Pick one for me
Track
Spatial Analysis1 problemPostGIS / SQL1 problemPython0 problemsRemote Sensing0 problemsCartography0 problemsWeb GIS0 problemsData Management0 problemsGIS Architecture0 problems
Level
Beginner2 problemsIntermediate1 problemAdvanced1 problemExpert0 problems
Hand in
SQL1 problemPython1 problemGeoJSON1 problemAnswers0 problemsSchema0 problemsDecisions0 problemsDataset file0 problems
Category
Data preparation0 problemsData quality1 problemSpatial analysis1 problemRaster analysis0 problemsCartography0 problemsDecision support3 problemsGeospatial systems0 problemsWeb delivery1 problem
Sign in to track progress
AdvancedSpatial analysisSQLClear all
  1. Not started, Urban share of each state, in SQLSpatial analysisSQL

    ST_Intersection for the pieces and ST_Area on geography for the metres — the overlay-and-measure pattern inside the database.

    PostGIS / SQLadvancedDifficulty: advanced300 XP~45 min5 checks

    You hand in a spatial SQL query.

    Datasets

    • United States states · Polygon · 51 features · EPSG:4326
    • Urban areas · Polygon · 2,143 features · EPSG:4326

    What you’ll do

    • Overlay polygons with ST_Intersection
    • Measure the pieces on geography rather than in degrees
    • Aggregate per state, keeping the states with nothing
    ST_IntersectiongeographyoverlayGROUP BYland useAlso trains Spatial Analysis
    Open problem