Slope, aspect, hillshade & contours from elevation data, plus NDVI, NDWI, NDBI and false-color composites from satellite imagery. Upload a GeoTIFF — all processing happens on the server.
Terrain / Elevation (single-band DEM)
Multispectral Imagery
8 Raster Operations, Explained
Slope
Terrain steepness, in degrees or percent, computed via Horn's method — a standard, well-established slope algorithm.
Aspect
The compass direction each point on the terrain faces (its direction of steepest descent).
Hillshade
Shaded relief imagery from a chosen sun azimuth and altitude.
Contour
Elevation contour lines at a chosen interval, exportable as GeoJSON, Shapefile, or KML.
NDVI
Normalized Difference Vegetation Index — highlights plant health and vegetation density from Red and NIR bands.
NDWI
Normalized Difference Water Index — highlights open water from Green and NIR bands.
NDBI
Normalized Difference Built-up Index — highlights urban/built-up areas from SWIR and NIR bands.
False Color Composite
Visualize any 3 bands as a custom RGB image — e.g. NIR-Red-Green to highlight vegetation.
Frequently Asked Questions
What file format do I need to upload?
GeoTIFF (.tif or .tiff) — either a single-band elevation DEM, or multi-band satellite imagery.
How does band mapping work for satellite imagery?
Bands (Red, Green, Blue, NIR, SWIR) are auto-detected from file metadata or common sensor conventions (like Landsat), always shown for you to confirm or override before running an index calculation.
My Landsat/Sentinel-2 download came as separate band files, not one image — do I need to combine them myself first?
No — upload each band file separately and this tool stacks them for you. Pick your imagery source (Landsat 4/5, Landsat 7, Landsat 8/9, Sentinel-2, or assign roles manually for anything else) and the correct band numbering is filled in automatically, since Landsat's older TM/ETM+ sensors and the newer OLI sensor genuinely use different band numbers for the same colors.
Can I limit processing to a specific area instead of the whole scene?
Yes — add an area of interest as a spatial file (GeoJSON, Shapefile, KML, GeoPackage), or as a CSV/Excel of coordinates. A spreadsheet works as a WKT polygon in one cell, an ordered coordinate list in one cell, or one row per boundary point with latitude/longitude columns — this tool builds and validates the boundary either way before using it.
What's the maximum file size?
200MB, processed in memory-bounded chunks so large DEMs and multi-band imagery are handled efficiently.
Is my uploaded data stored on your servers?
No. Files are processed in memory for your request and discarded immediately afterward.
Is this free to use for commercial or research work?
Yes, free for any use. For larger remote sensing or terrain analysis projects, Sagarmekhla GIS Consultancy offers professional GIS and remote sensing services.
Need custom terrain analysis or remote sensing work? Our team provides professional GIS, remote sensing, and spatial analysis services for government, research, and industry.
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