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Kharita Challenges

Problems

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

7 of 59 problems

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Track
Spatial Analysis2 problemsPostGIS / SQL1 problemPython3 problemsRemote Sensing1 problemCartography1 problemWeb GIS0 problemsData Management7 problemsGIS Architecture0 problems
Level
Beginner1 problemIntermediate4 problemsAdvanced2 problemsExpert0 problems
Hand in
SQL1 problemPython1 problemGeoJSON1 problemAnswers4 problemsSchema0 problemsDecisions0 problemsDataset file0 problems
Category
Data preparation7 problemsData quality7 problemsSpatial analysis14 problemsRaster analysis6 problemsCartography5 problemsDecision support11 problemsGeospatial systems3 problemsWeb delivery6 problems
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Data qualityClear all
  1. Not started, Which airport codes will break the schedule join?Data qualityAnswers

    Audit a registry's identifiers before they become a join key: missing, malformed and duplicated codes, and positions that are only approximate.

    Data ManagementbeginnerDifficulty: beginner130 XP~25 min5 checks

    You hand in your answers as values.

    Dataset

    • World airports · Point · 893 features · EPSG:4326

    What you’ll do

    • Find nulls, duplicates and malformed values in an identifier column
    • Distinguish a key defect from a position defect
    • Report counts the integration can be sized against
    data qualityidentifiersjoin keysaviationAlso trains Python
    Open problem
  2. Not started, Accept the rasters, or send them backData qualityAnswers

    The checks a data manager runs on delivered rasters before anyone analyses them: extent, nodata, value range, and whether the figures are plausible for the place.

    Data ManagementintermediateDifficulty: intermediate200 XP~35 min6 checks

    You hand in your answers as values.

    Datasets

    • Greater London elevation (Copernicus DEM GLO-30) · Raster · EPSG:4326
    • Greater London land cover 2021 (ESA WorldCover 10 m) · Raster · EPSG:4326
    • Greater London, Sentinel-2 red and NIR, 11 July 2025 · Raster · EPSG:32630

    What you’ll do

    • Read raster metadata and full-resolution statistics
    • Distinguish nodata from valid extremes
    • Record facts a later dispute can start from
    raster QAnodatametadataacceptanceLondonAlso trains Remote Sensing
    Open problem
  3. Not started, When the attributes and the geometry disagreeData qualityAnswers

    A reference gazetteer carries a latitude and a longitude column beside its geometry. Audit how far apart they are, and what else does not add up.

    Data ManagementintermediateDifficulty: intermediate200 XP~35 min5 checks

    You hand in your answers as values.

    Dataset

    • Populated places · Point · 1,251 features · EPSG:4326

    What you’ll do

    • Compare each feature's geometry to the coordinate attributes it carries
    • Count the disagreements at two thresholds and identify the worst
    • Find keys the downstream spreadsheet cannot distinguish
    data qualitygazetteerhaversineduplicatesglobalAlso trains Python
    Open problem
  4. Not started, Which places can the emissions change map actually compare?Data qualityPython

    Audit two-date indicator coverage and map the places excluded before showing a climate trend.

    Data ManagementintermediateDifficulty: intermediate290 XP~45 min6 checks

    You hand in a Python script.

    Datasets

    • Countries · MultiPolygon · 241 features · EPSG:4326
    • CO2 per capita by country, 2010 and 2022 · Point · 241 features · EPSG:4326

    What you’ll do

    • Audit missingness before a two-date map is interpreted
    • Prevent a many-to-many join on nonstandard ISO codes
    • Show complete and incomplete coverage on real country polygons
    World Bankdata qualitymissing datacategorical mapglobalAlso trains Python, Cartography
    Open problem
  5. Not started, Which ports in the registry are the same port?Data qualityAnswers

    Find probable duplicates in a facility registry by combining a name match with a distance rule — and separate them from the honest homonyms.

    Data ManagementintermediateDifficulty: intermediate190 XP~30 min4 checks

    You hand in your answers as values.

    Dataset

    • Ports · Point · 1,081 features · EPSG:4326

    What you’ll do

    • Find repeated identifiers in a registry
    • Combine an attribute match with a spatial rule to separate duplicates from homonyms
    • Size the missing attribute that would resolve the rest
    data qualitydeduplicationhaversineregistryglobalAlso trains Spatial Analysis
    Open problem
  6. Not started, Are these country polygons fit to assign cities to?Data qualitySQL

    A point-in-polygon audit that exposes what 1:50m generalisation does to a coastline — and which places the attribute and the geometry disagree about.

    PostGIS / SQLadvancedDifficulty: advanced300 XP~45 min5 checks

    You hand in a spatial SQL query.

    Datasets

    • Populated places · Point · 1,251 features · EPSG:4326
    • Countries · MultiPolygon · 241 features · EPSG:4326

    What you’ll do

    • Join points to the polygon containing them with an outer join
    • Compare an attribute to a derived value with NULL-safe semantics
    • Return the disagreement list, including the points nothing contains
    ST_Containsouter joinIS DISTINCT FROMgeneralisationdata qualityAlso trains Data Management
    Open problem
  7. Not started, Which big cities does the gazetteer not know?Data qualityGeoJSON

    Test one layer's completeness against another: large urban footprints with no populated place inside them at all.

    Data ManagementadvancedDifficulty: advanced300 XP~45 min5 checks

    You hand in a GeoJSON result.

    Datasets

    • Urban areas · Polygon · 2,143 features · EPSG:4326
    • Populated places · Point · 1,251 features · EPSG:4326

    What you’ll do

    • Measure footprint area in an equal-area projection and apply a size floor
    • Test each footprint for containment of any point from a second layer
    • Return the uncovered footprints with the area that says how much they matter
    completenessspatial joinequal-areagazetteerglobalAlso trains Spatial Analysis
    Open problem