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Kharita Challenges

Problems

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

3 of 59 problems

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Track
Spatial Analysis3 problemsPostGIS / SQL1 problemPython1 problemRemote Sensing0 problemsCartography0 problemsWeb GIS0 problemsData Management2 problemsGIS Architecture0 problems
Level
Beginner4 problemsIntermediate3 problemsAdvanced3 problemsExpert2 problems
Hand in
SQL1 problemPython1 problemGeoJSON1 problemAnswers0 problemsSchema0 problemsDecisions0 problemsDataset file0 problems
Category
Data preparation2 problemsData quality1 problemSpatial analysis3 problemsRaster analysis2 problemsCartography1 problemDecision support5 problemsGeospatial systems0 problemsWeb delivery0 problems
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Spatial AnalysisAdvancedSpatial analysisClear all
  1. Not started, How much of each state is built up?Spatial analysisPython

    Overlay the urban footprints on the states in an equal-area projection and credit each side of a state line only what lies on it.

    PythonadvancedDifficulty: advanced320 XP~55 min5 checks

    You hand in a Python script.

    Datasets

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

    What you’ll do

    • Reproject both layers to an equal-area CRS
    • Clip the urban footprints to the states with an overlay
    • Sum clipped area per state and express it as a share of the state's area
    GeoPandasoverlayequal-areaAlbersland useAlso trains Spatial Analysis, Data Management
    Open problem
  2. 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
  3. Not started, Which metros straddle an international border?Spatial analysisGeoJSON

    Overlay 2,143 urban footprints on 241 countries and keep the ones with real built-up area on both sides of a line.

    Spatial AnalysisadvancedDifficulty: advanced320 XP~50 min5 checks

    You hand in a GeoJSON result.

    Datasets

    • Urban areas · Polygon · 2,143 features · EPSG:4326
    • Countries · MultiPolygon · 241 features · EPSG:4326

    What you’ll do

    • Overlay a footprint layer on a boundary layer
    • Measure the pieces in an equal-area projection and apply a minimum
    • Aggregate pieces back to the footprint and keep the multi-country ones
    overlayequal-areaaggregationbordersglobalAlso trains Data Management
    Open problem