SPOT DEM

Add a new dimension to your geographic data bases

A SPOT DEM is a digital elevation model produced by automatic correlation of stereopairs acquired by the HRS instrument on SPOT 5.

Unlike a digital terrain model (DTM), which describes the distribution of terrain or “bare earth” heights, a DEM includes “first surface” elevations including vegetation and man-made structures.

Sampling

A SPOT DEM is a gridded file with step sizes of 1 second of arc (30 m on the equator, E/W dimensions vary according to the latitude).
Resampling to 20 m available.

Unmatched performance

Absolute horizontal accuracy without ground control points

The absolute horizontal accuracy is the positional error in the DEM with respect to the ground truth. For a SPOT DEM, this depends on the dimensions of the area of interest or on the availability of Reference3D (French defence database) data for this area.

Absolute vertical accuracy without ground control points

The absolute vertical accuracy is the elevation error in the DEM with respect to the ground truth. It depends mainly on the slope of the terrain.

Absolute accuracy	Area covered by Reference 3D (when available)	Area of 100,000 to 150,000 km² (when available)	Area < 7200 km²
Horizontal	< 10 m	< 10 m	< 30 m
Vertical (slope < 20%)	< 10 m	< 10 m	< 20 m

^{* Values guaranteed with 90% confidence}

A made-to-measure response

Datum and projection

WGS84
UTM WGS84 or other projection on request

Size / Frame

The SPOT DEMs can be framed to match the perimeters of your area of interest. With a price per square kilometre, you will be able to optimize your budget.

Format

The SPOT DEM come in the Dimap format (or DTED as an option).