Maps / Slope map

Slope maps that show where you can build.

A slope map measures how steep the ground is, cell by cell, from elevation data. It shows at a glance which land is flat enough to develop, where grading gets expensive, and where erosion and landslides are a risk.

Get a slope map for your site See an example

Example

Steep ridges, flat valley floors.

This sample covers about 30 × 32 km near Jacksboro, Tennessee, where the Jacksboro Fault cuts through the Cumberland Mountains. Bright areas are steep; dark areas are flat.

Slope map of the Jacksboro Fault area, Tennessee. Steep mountain slopes over 25 percent, shown in light gold, cover almost half the area. A flat valley floor, shown dark, runs diagonally along the fault, with narrow flat stream valleys branching through the hills to the west. — Percent slope, five classes. North is up. Calculated by PentoGIS from USGS elevation data at about 90 m resolution (the Jacksboro Fault sample elevation model distributed with Matplotlib). For a real project we use finer data, usually 1 to 10 m.

Slope classes in the example area
Slope	Class	What it usually means	Share of area	km²
0–5%	Flat to gentle	Suits most uses; the easiest and cheapest ground to build on.	7.5%	72
5–10%	Moderate	Buildable with some grading; fine for most roads and parking.	11.4%	108
10–15%	Strong	Buildings and roads need careful grading and drainage design.	11.8%	113
15–25%	Steep	Limited development; erosion control and engineering required.	22.3%	212
25% and over	Very steep	Usually avoided; high erosion and landslide risk.	47.0%	447

Thresholds vary by jurisdiction and use. We classify slope to match your local ordinance, design standard, or project brief.

Who uses slope maps

One map, many decisions.

Site selection and development

Screen parcels for buildable area before buying land or drawing a site plan.

Stormwater and erosion

Find steep, bare slopes where runoff and soil loss need controls.

Roads, trails and access

Plan routes within grade limits, such as the 5% maximum running slope for accessible routes.

Landslide and hazard screening

Flag steep ground for geotechnical review, together with soils and geology.

Solar and agriculture

Combine slope with aspect to find gentle, sun-facing land for panels or crops.

Planning and zoning

Map steep-slope overlay districts and check proposals against them.

What you get

Ready for GIS, CAD, and the board meeting.

Slope raster (GeoTIFF) in percent or degrees
Slope classes as polygons (shapefile, GeoPackage, or file geodatabase)
Print-ready maps (PDF and PNG) with your site boundary
Area by slope class for each parcel or site
Optional aspect, hillshade, and contour layers

Elevation data

We source the best available model: USGS 3DEP lidar (1 m in much of the US), 10 m national coverage, or your own survey.

Slope analysis

Calculate slope for every cell, then classify it into the thresholds you need and clean up slivers.

Maps and numbers

Deliver maps, data, and a short summary of buildable and constrained area.

Have a site in mind?

Send us the location. We'll map the slope.

Share an address, a parcel ID, or a boundary file, and tell us what you're planning.

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