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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 Analysis4 problemsPostGIS / SQL0 problemsPython0 problemsRemote Sensing6 problemsCartography0 problemsWeb GIS0 problemsData Management3 problemsGIS Architecture0 problems
Level
Beginner1 problemIntermediate0 problemsAdvanced2 problemsExpert0 problems
Hand in
SQL0 problemsPython0 problemsGeoJSON2 problemsAnswers2 problemsSchema0 problemsDecisions0 problemsDataset file1 problem
Category
Data preparation7 problemsData quality7 problemsSpatial analysis6 problemsRaster analysis3 problemsCartography1 problemDecision support9 problemsGeospatial systems3 problemsWeb delivery0 problems
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Data ManagementRaster analysisClear all
  1. Not started, What is Greater London made of?Raster analysisAnswers

    A class histogram on a 10 m land-cover raster: the shares a planning document quotes, and the reason a pixel count is not quite an area.

    Remote SensingbeginnerDifficulty: beginner140 XP~25 min5 checks

    You hand in your answers as values.

    Dataset

    • Greater London land cover 2021 (ESA WorldCover 10 m) · Raster · EPSG:4326

    What you’ll do

    • Read a categorical raster and count pixels per class
    • Express classes as shares of the valid pixels
    • State what the number is and is not
    land coverWorldCoverhistogramrasterLondonAlso trains Data Management
    Open problem
  2. Not started, Mean NDVI per borough, across a projection boundaryRaster analysisGeoJSON

    Zonal statistics where the raster is in UTM and the polygons are in WGS 84: reproject the right layer, compute the index per borough, and hand back a map.

    Remote SensingadvancedDifficulty: advanced300 XP~50 min7 checks

    You hand in a GeoJSON result.

    Datasets

    • Greater London, Sentinel-2 red and NIR, 11 July 2025 · Raster · EPSG:32630
    • London boroughs · Polygon · 33 features · EPSG:4326

    What you’ll do

    • Recognise a CRS mismatch between a raster and a vector layer
    • Reproject the vector layer rather than resample the raster
    • Compute a per-zone mean of a derived index
    NDVIzonal statisticsCRSUTMSentinel-2LondonAlso trains Spatial Analysis, Data Management
    Open problem
  3. Not started, Screen Newham’s greening gridProjectRaster analysis3 steps

    Audit a real land-cover chip, deliver a measured grid file, and identify cells for field verification.

    Remote SensingadvancedDifficulty: advanced600 XP~100 min10 checks

    Worked in 3 steps, each checked before the next one opens.

    1. Audit the class chip · Answers
    2. Hand over the measured grid · Dataset file
    3. Map field-verification cells · GeoJSON

    Datasets

    • Newham WorldCover 2021 class chip · Raster · EPSG:4326
    • London boroughs · Polygon · 33 features · EPSG:4326

    What you’ll do

    • Audit class counts in the clipped raster
    • Prepare a traceable borough grid as an uploaded GIS file
    • Return only cells that meet a stated greening screen
    NewhamWorldCoverurban greeningoffline rasterAlso trains Data Management, Spatial Analysis
    Open project