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DEM & Contour Mapping Studio

Elevation grids, contour maps, profiles and terrain analysis for any place on Earth.

Mark any area on Earth and the studio fetches a digital elevation model as a regular grid in UTM or geographic coordinates, traces contours at the interval you choose, and lays out a print-ready map in five styles, from colour relief to a spot-height exercise sheet. It cuts topographic profiles, builds a 3D model, computes the hypsometric curve, integral and slope distribution, and exports the grid and contours for Surfer, QGIS, ArcGIS and AutoCAD Civil 3D.

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DEM & Contour Mapping Studio

Overview

Three elevation models are available. The SRTM composite (about 30 m) merges NASA’s Shuttle Radar Topography Mission with USGS 3DEP, GMTED2010 and ETOPO1; its tiles are decoded in your browser, so even large grids arrive in seconds. Copernicus GLO-30 (30 m) and GLO-90 (90 m), the global models of the European Space Agency, are read as full-precision floating-point tiles and resampled bilinearly. In UTM the nodes fall on round eastings and northings.

Contours are traced with the marching-squares algorithm and smoothed for display; every fifth line (or the step you set) is an index contour with its value. The map sheet carries a graduated border, a coordinate grid, a north arrow, a boxed legend, a graphic scale with representative fraction and the coordinate reference. Change the style, interval, colours or labels and the map redraws at once without fetching again.

Trace a section line across the relief to get a topographic profile with distance, elevation, total ascent and descent, mean and maximum slope and the vertical exaggeration; the section is drawn on the map as A–B. Terrain statistics include relief, mean slope after Horn (1981) and the hypsometric curve and integral of Strahler (1952), which describe the erosional stage of the landscape.

What you enter · What you get

What you enter

  • Area drawn on the map or typed bounds
  • Elevation model, grid spacing and coordinate system (UTM or geographic)
  • Map style, contour interval, index contour, spot spacing, colours and labels
  • Profile line (two to twenty points)

What you get

  • Print-ready map in five styles: colour relief with contours, contours only, spot heights only (exercise), spot heights with contours, spot heights on relief
  • Topographic profile with ascent, descent, slope and vertical exaggeration
  • 3D terrain model with adjustable vertical exaggeration
  • Hypsometric curve and integral, slope distribution
  • Grid in CSV, XYZ and ESRI ASCII with .prj; contours in GeoJSON and DXF; map in PNG and SVG; PDF report

How it works in the field

Draw the area
Choose the model, spacing and style
Fetch and preview the map
Cut a profile
Export

Method and equations

Terrarium decoding

Each terrain tile stores elevation in the red, green and blue channels of a PNG image; heights are sampled bilinearly at every grid node.

h = (R × 256 + G + B / 256) − 32768

Bilinear resampling

A node inside a cell takes the area-weighted mean of the four surrounding cell values.

z = z00(1−u)(1−v) + z10u(1−v) + z01(1−u)v + z11uv

Contours

Marching squares: each grid cell is classified by which corners lie above the level, and the crossing is located by linear interpolation along the cell edge.

t = (L − za) / (zb − za)

Slope and hillshade

Slope and aspect from Horn’s third-order finite differences; hillshade with a light source at azimuth 315° and altitude 45°.

S = arctan √((∂z/∂x)² + (∂z/∂y)²)

Hypsometric integral

Elevation–relief ratio approximation: near 1 marks a young, little-eroded landscape; near 0, an old, deeply eroded one.

HI = (hmean − hmin) / (hmax − hmin)

Who uses it

Geologists preparing base mapsSurveyors and GIS analystsCivil and road engineersHydrologists and plannersTeachers and students (spot-height exercises)

Standards and references

  1. Farr, T.G. et al. (2007). The Shuttle Radar Topography Mission. Reviews of Geophysics, 45, RG2004.
  2. European Space Agency (2021). Copernicus Global Digital Elevation Model (GLO-30 and GLO-90).
  3. Danielson, J.J. & Gesch, D.B. (2011). Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010). USGS Open-File Report 2011–1073.
  4. Amante, C. & Eakins, B.W. (2009). ETOPO1 1 Arc-Minute Global Relief Model. NOAA Technical Memorandum NESDIS NGDC-24.
  5. Horn, B.K.P. (1981). Hill shading and the reflectance map. Proceedings of the IEEE, 69(1), 14–47.
  6. Strahler, A.N. (1952). Hypsometric (area-altitude) analysis of erosional topography. GSA Bulletin, 63, 1117–1142.
  7. Lorensen, W.E. & Cline, H.E. (1987). Marching cubes: a high resolution 3D surface construction algorithm. Computer Graphics, 21(4), 163–169.
Results support professional judgement. They do not replace a licensed engineer’s or geologist’s sign-off.

At a glance

Category
Terrain & maps
Runs on
Phone, tablet and desktop browser
Export
PNG, SVG, GeoJSON, DXF, CSV, XYZ, ESRI ASCII + .prj, PDF
Access
Subscribers

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