Terrain Analysis & Hydrology Tool
Cloud3 free/dayTerrain analysis on a DEM: slope, aspect, hillshade, TRI, roughness and contours, plus sink fill, flow accumulation and stream extraction. Free daily quota.
Drag files here, or click to browse
Supports TIFF
Choose fileSign-in required; cloud tasks draw from your cloud credits by weight (see pricing for free/Pro rules).
After submission this page polls the job every 2 seconds for up to about 11 minutes; if it times out, please resubmit (the server allows up to 10 minutes per job).
The analysis result has no inline preview — download it when the job finishes (GeoTIFF results can be opened in the GeoTIFF Viewer for inspection). Only the input DEM is thumbnailed locally before upload.
What is it? Terrain analysis on a DEM: slope, aspect, hillshade, TRI, roughness, TPI and contours (GDAL), plus sink fill, flow accumulation and stream extraction (WhiteboxTools). Set a Z-factor whenever the DEM's vertical units differ from its horizontal units; the input DEM is thumbnailed locally before upload and the result has no inline preview.
TL;DR: Terrain and hydrology analysis on a GeoTIFF DEM: slope, aspect, hillshade, TRI, roughness, contours, sink fill, flow accumulation, streams.
How to use
- Sign in and pick a GeoTIFF DEM — a locally rendered thumbnail lets you eyeball it before upload.
- Choose the analysis to run; set the Z-factor for slope or hillshade if the DEM's vertical units differ from its horizontal ones.
- Wait for the cloud job and download the result — open GeoTIFF outputs in the GeoTIFF Viewer to inspect them.
FAQ
What can I compute?
Slope/aspect/hillshade/TRI/roughness/contours and hydrology steps such as sink fill and stream extraction.
Can I preview the result on the page?
No — only the input DEM is thumbnailed locally. Download the result when the job finishes; GeoTIFF results can be opened in the GeoTIFF Viewer for inspection.
When are files deleted?
Cloud files follow the configured retention window.
When do I need to set a Z-factor?
Whenever the DEM's vertical units differ from its horizontal units — typically a GeoTIFF in geographic degrees (horizontal) with metre elevations (vertical). Without the Z-factor, slope and hillshade results are meaningless. TRI, roughness and TPI have no Z-factor; their values come out in the DEM's vertical units, so unit-mismatched DEMs distort them the same way.
Does it delineate a watershed or basin boundary from an outlet point?
No — and that is the honest boundary. It computes the hydrology building blocks: fill depressions, flow accumulation and the stream network. Pour-point or basin delineation (choosing an outlet and tracing the contributing area) is not supported. If you need basin boundaries, compute the flow accumulation here and take it into QGIS or WhiteboxTools for the final delineation step.
Which DEM files can I upload?
GeoTIFF only — the input is a single GeoTIFF DEM. SRTM .hgt, ESRI ASCII grids, zipped tiles or DTED are not accepted; convert them to GeoTIFF first (the Raster Reproject or vector conversion tools handle GeoTIFF sides, but format imports are out of scope here).
Is it free? Do I need an account?
Yes — it runs on the free daily cloud quota, but it does require a sign-in because processing happens on the server (GDAL for surface analysis, WhiteboxTools for hydrology). Nothing is installed: the whole workflow runs from the browser.
Are these the same algorithms as GDAL DEM and WhiteboxTools?
Yes — surface analysis (slope/aspect/hillshade/TRI/roughness/TPI/contours) is GDAL's DEM toolchain (MIT/X11), hydrology (fill-depressions/flow-accumulation/streams) is WhiteboxTools (MIT). The page exposes the common options such as Z-factor and contour interval; for exotic parameters, the CLI tools offer more.
Examples
- Upload a DEM (GeoTIFF) → pick terrain.hillshade → download the shaded relief; or terrain.contours for contour GeoJSON
- Upload a DEM → terrain.slope with Z-factor 111120 (degrees horizontal, metres vertical) → download the slope raster for a steepness map.
Supported formats
Limitations
- Requires an account and cloud quota.
- Slope and hillshade accept a Z-factor: set it whenever the DEM's vertical units differ from its horizontal units (e.g. degrees vs meters), or slope results are meaningless.
- TRI, roughness and TPI are elevation-difference indices: their values are in the DEM's vertical units (e.g. meters) and they offer no Z-factor — unit-mismatched DEMs distort them the same way.
- The contour interval is in the input DEM's elevation units.
- Surface analysis runs on GDAL (MIT/X11); hydrology on WhiteboxTools (MIT).
- Contour and stream outputs are vectors or rasters and can be large for big datasets; larger DEMs take longer to process.
- Only the input DEM is thumbnailed locally before upload (256 px long edge); the analysis result has no inline preview — download it and open GeoTIFF results in the GeoTIFF Viewer.
Privacy
This tool has no local processing path: your file is uploaded over an encrypted connection to our own VPS, used only for this job, stored for 1 days by default and auto-deleted — or delete it earlier at any time.