MapTools
NOV29DAY 29 / 30

#30DayMapChallenge 2026

Raster

Tell a spatial story one pixel at a time.

4 map ideas4 tools3 data sources1 practical tip
01

AI-ASSISTED · EDITOR-REVIEWED

Theme brief

Raster data represents space as cells: imagery, elevation, temperature, land cover and modeled surfaces. Resolution is part of the claim; do not zoom beyond what the cell size or source accuracy can support.

Official prompt

“Do something cool with pixels.”

30DayMapChallenge 2026
02

WAYS IN

Four map ideas

  1. 01

    Compute a simple vegetation index and explain every processing step.

  2. 02

    Blend hillshade with elevation without using political boundaries.

  3. 03

    Compare two dates of the same satellite scene.

  4. 04

    Turn a categorical land-cover raster into a carefully limited palette.

03

IN THE DIRECTORY

Recommended tools

QGIS

Its raster calculator, classification and layout tools cover an end-to-end desktop workflow.

Open source · View details

Google Earth Engine

Processes large satellite archives without downloading every scene.

Freemium · View details

Copernicus Browser

A fast visual route into Sentinel imagery and custom band combinations.

Free · View details

GDAL/OGR

The dependable command-line layer for conversion, clipping, warping and optimization.

Open source · View details
04

START WITH A CLEAR LICENSE

Data sources

Copernicus Sentinel-2 imagery

Multispectral imagery with frequent global coverage.

 Free, full and open under Copernicus terms USGS/NASA Landsat

A long-running Earth observation archive for change over time.

 U.S. government data · attribution requested Copernicus DEM

Global elevation models at 30 m and 90 m spacing.

 Free use under Copernicus terms

Licenses are a planning aid, not legal advice. Check the source record and version you actually download; terms can vary within a catalog.

05

BEFORE YOU EXPORT

Cartography check

Include acquisition date, pixel size and processing level. Those details determine what the raster can credibly show.

06

COMMUNITY MAPS

Selected work

Selections begin after this theme closes.

First participate officially by posting publicly with #30DayMapChallenge. You can then suggest that original post for our independent MapTools picks. We link to the source, credit every author and use images only with permission.

Suggest for MapTools picks