How to open a GeoTIFF / DEM file online
You don’t need QGIS or ArcGIS just to look at an elevation file. Here’s how to open a GeoTIFF DEM in your browser in about ten seconds, and how to get the most out of what you see.
Short version: open the viewer, drag your .tif onto the page, and the terrain appears on the map. Your file is never uploaded.
What you need
A single-band GeoTIFF elevation raster, usually ending in .tif or .tiff. This is the standard format for a DEM (Digital Elevation Model). If you don’t have one yet, see where to download free DEMs. If you’re not sure what a DEM is, read What is a DEM?
Step 1: Open the viewer and drop your file
Go to the viewer and drag your file onto the page, or click the drop zone to browse. You can also drop a file straight onto the home page.
Large files are read in pieces, with a progress bar. If the raster has more than about 16 million cells it is shown as a reduced-resolution preview, and the Details panel tells you so.
Step 2: Read the map
The terrain appears at its real-world location on the map, whatever coordinate system the file uses. Two things are drawn together in the default Shaded style:
- Color shows elevation. The legend in the panel maps colors to heights, from the lowest value in the file to the highest.
- Shading shows shape. A simulated sun lights the terrain so ridges, valleys, cliffs and even old roads become visible.
Step 3: Adjust the view
| Control | What it does | When to use it |
|---|---|---|
| Style | Shaded (color + light), Hillshade (light only) or Color (elevation only) | Use Hillshade to judge fine texture, Color to read elevations. |
| Sun direction / height | Where the light comes from and how high it is | Features that run parallel to the light disappear. Rotate the sun to reveal them. |
| Vertical exaggeration | Stretches heights to make relief more dramatic | Flat terrain such as plains or river valleys looks better at 3–5×. |
| Color ramp | Five palettes, plus a reverse option | Pick a high-contrast ramp such as Viridis for presentations. |
| Range and “Trim 2–98%” | Sets which elevations map to the ends of the color scale | If the map looks washed out, a few extreme values are stretching the scale. Trim them. |
| Opacity | See the basemap through the terrain | Check that features line up with roads, rivers or buildings. |
Step 4: Read heights and export
Move the cursor over the terrain to read the exact elevation and the latitude/longitude underneath it. When you’re happy with the view, press Download PNG to save the rendered terrain as an image.
About the PNG: it is the raster’s own pixel grid, so with some projections (for example Canada’s Lambert grid) north is not exactly “up” in the image. The elevation range is baked into the colors, so note the legend values if you share it.
Tips
- Everything looks one color? Press Trim 2–98%, or type your own range. See the troubleshooting guide for other causes.
- Other formats. Esri ASCII grids (
.asc), SRTM.hgttiles and Erdas.imgfiles need converting first. With GDAL installed:gdal_translate input.hgt output.tif. QGIS can do the same through Raster → Conversion → Translate. - Compression. Uncompressed, LZW, DEFLATE, ZSTD, PackBits, LERC and JPEG-compressed GeoTIFFs all open.
- Colour photos are not DEMs. An orthomosaic (an aerial photo) has three bands and can’t be shown as elevation. Export the DEM/DSM from your processing software instead.
Try it now
No file handy? The viewer has a one-click sample of real 1 m lidar terrain from Gatineau Park.