Turn elevation grids into beautifully precise contour-line maps. Reveal terrain with elevation bands, adjust isolines and export an editable SVG—all without uploading your data.
⌁Creating your contour map…Generated locally, no elevation data leaves this device.
⌖
Zoom using +/− and scroll inside the map. Click a map point or focus the map and use arrow keys to inspect elevations (Shift + arrows moves five samples). Contours are calculated from a triangulated interpolation of the grid.
Grid size—
Elevation range—
Contour levels—
Missing samples—
MAP LEGEND
Elevation spectrum
m
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Load a grid to inspect its elevations.
THE ESSENTIALS
From grid to geographic insight.
01 / IMPORT
Upload structured elevation data
Bring a numeric CSV/TSV, a 2D JSON array, or an Esri ASCII raster. Row one is the top of the grid; ASC headers preserve native grid coordinates.
02 / STYLE
Reveal the elevation structure
Define contour spacing, line hierarchy, color ramps and labels. Missing-data cells remain gaps, never fabricated heights.
03 / EXPORT
Keep every line editable
Export a self-contained SVG for vector editing, a PNG preview for sharing, or CSV/DXF contour coordinates for further analysis and CAD tools.
Scope and accuracy
This tool creates contours from sample-point elevations using a piecewise-linear surface. It does not geocode, reproject, download terrain, infer missing elevations, or determine measurement units. For surveying, hazard assessment and navigation, verify source resolution, datum and CRS independently. PNG exports depend on the browser’s canvas-size limits.
Frequently asked questions
Which elevation grid formats work?
Numeric rectangular CSV, TSV and whitespace TXT; a 2D JSON array (or {"grid":[...]}); and Esri ASCII .asc with NCOLS/NROWS, CELLSIZE and matching lower-left origin coordinates.
Does the SVG preserve geographic coordinates?
The drawing uses grid units and includes ASCII-grid origin and cell-size metadata when available. A contours CSV export converts interpolated vertices to ASC source coordinates. Neither output establishes a CRS or reprojects data.
Can I generate contours from photos or GeoTIFF?
Not directly. First export a numeric elevation grid, for example Esri ASCII raster from GIS software. Image brightness is not automatically elevation.
Using Contour Map Generator
Generate contour lines and elevation bands from supported grid inputs, review the interpolated surface and export visual or vertex data outputs.
Workflow
Import a supported CSV, TSV, TXT, JSON or Esri ASCII grid and confirm dimensions and missing cells
choose contour levels and inspect the generated surface and labels
export SVG/PNG, vertex CSV or DXF polylines and review their coordinate assumptions.
Example
Load a small elevation grid with known values, compare one contour level against the input cells, inspect blank regions for missing corners and export both SVG and vertex CSV.
Limits and data handling
The model uses four-triangle piecewise-linear interpolation and does not infer a coordinate reference system, datum or units. Unit labels do not convert values. Missing grid corners can prevent interpolation, and this is not a survey surface. DXF contains 2D polylines rather than a 3D terrain mesh. Inputs are bounded to 4 MB, 50,000 samples, 420 cells per side and 48 levels. Inspect the chosen levels and units before using exports.
FAQs
Does the generator convert between elevation units?
No. Unit labels annotate values but do not convert them.
Is the DXF export a 3D terrain model?
No. It contains 2D contour polylines, not a triangulated 3D mesh.
