AI-ASSISTED · EDITOR-REVIEWED

Theme brief

Sight invites both physical visibility and visual perception. A terrain viewshed is the obvious route, but you can also map sightlines, skyline obstruction, street-level enclosure or the places where signs and landmarks become visible.

Official prompt
“How do you see something? Maybe map a viewshed?”
30DayMapChallenge 2026

02

WAYS IN

Four map ideas

01
Calculate the visible landscape from a summit or observation tower.
02
Map which homes can see a proposed building or wind turbine.
03
Measure landmark visibility along a walking route.
04
Create a city map based on eye-level openness rather than plan view.

03

IN THE DIRECTORY

Recommended tools

QGIS

Combines elevation rasters with viewshed plugins and strong cartographic control.

Open source · View details

Google Earth

Useful for quick terrain inspection and communicating a viewpoint in 3D.

Free · View details

Copernicus Browser

Helps locate and inspect elevation and imagery inputs before analysis.

Free · View details

GRASS GIS

Its raster visibility tools suit repeatable, advanced terrain workflows.

Open source · View details

04

START WITH A CLEAR LICENSE

Data sources

Copernicus DEM

Global elevation models at 30 m and 90 m spacing.

Free use under Copernicus terms NASA Shuttle Radar Topography Mission

Near-global elevation data commonly available at about 30 m.

Open U.S. government data · cite NASA Local open LiDAR

Search OpenTopography and national portals; verify local reuse terms.

Varies by dataset

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

State observer height, target height and terrain resolution. Those three choices can change the visible area dramatically.

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