Elevation1 DSM Technical Information

Elevation1 products
  1-m posting DSM Orthomosaic (8 bits)
Method Automatic stereo matching including auto-filtering of artefacts followed by enhanced editing. After editing tasks, all remaining voids are interpolated. Large voids over areas that are not flat are filled in with stereo data. Final visual quality check. A pan-sharpened orthomosaic is also generated (geometrically seamless, but not radiometrically). The cutline between each image is automatic. No overall radiometric optimization. Final visual quality check.
Manual editing level
  • Detection of water bodies (sea, lake, large river) and DSM flattening.
  • Removal of main artefacts (spike, hole).
  • Manual editing.
 
Source data Pléiades Stereo or Tristereo pair(s), Pan-Sharpened, Primary, JPEG 2000 Regular.
Grid spacing 1m 50cm
Accuracy Absolute XY*
  • With GCPs: 1.5m CE90.
  • With Ref3D GCPs: 6 to 10m CE90**.
  • Without GCPs: 8.5m to 10.5m CE90.
  • With GCPs: 1.5m CE90.
  • With Ref3D GCPs: 6 to 10m CE90**.
  • Without GCPs: 8.5m to 10.5m CE90.
Absolute Z*
  • With GCPs: 1.5m LE90.
  • With Ref3D GCPs: 6 to 10m LE90**.
  • Without GCPs: up to 10m LE**.
 
Relative
  • XY: 1.5m CE90.
  • Z: 1.5m LE90**.
  • 1.5m CE90
Format AsciiGrid or GeoTIFF. GeoTIFF
Projection Geo WGS84 or UTM / WGS84 (custom projection on request).
Vertical Unit Metres
Vertical reference Elevations above mean sea level (ref. = EGM96).
Accuracy level The accuracy specification of Elevation1 (with GCPs) is similar to the HRE10 NGA classification*.
GCPs
  • Ground control points can help to attain optimal accuracy.
  • The customer can provide accurate GCPs (~10cm XYZ) that are visible in the stereopair.
AOI
  • Large AOIs can be covered by adjacent stereopairs; the DSM mosaic will be seamless with no edge effect.
  • A minimum width of 10km is required.
  • Minimum area = 100 sq.km. / Maximum area = 2,000 sq.km. (larger areas will be considered on a case-by-case basis).
NoData value
  • The value –32767 is set for areas where the elevation is not determined (around AOI).
  • Potential clouds (if any) are considered as ‘No Data’.
Metadata No additional metadata is provided with the DSM.
Tiling DSM 1m tile is 10km x 10km (~600 Mb).
B/H ratio
  • The optimal B/H ratio is in the range of [0.3 – 0.6].
  • A high ratio (i.e. 0.6) is suitable for flat areas.
  • A low ratio (i.e. 0.3) is suitable for steep terrain.
Availability Product limited to mineral or open areas with little (or low) vegetation and few buildings. Urban areas are only proposed on request with a custom price. Perfect for micro-relief in arid areas.

 

Elevation1 DSM Technical Information