Terrain

Three queries read the surface itself, independently of any route. Pick the one that matches the shape of the question:

• terrainSamples for readings at coordinates you already know.
• terrainProfile for readings along a line — an elevation profile as data.
• terrainGrid for readings across an area whose features are not yet located, such as finding high ground or a slope facing a given direction.

All three return the same TerrainSample shape and read from the same digital elevation model, so a value means the same thing whichever query produced it. Coordinates are [longitude, latitude] in WGS 84, elevations are in meters above sea level, and slope is in degrees.

The sample

aspectOctant and steepnessBand use the same vocabulary as the aspect and steepness map overlays, so a value you read here matches the legend a user sees on the map.

Every result also carries zoom and resolutionMeters, the DEM tile zoom the reading was taken at and the ground distance one pixel covers there, so a reading can be reproduced later.

terrainSamples

Readings at specific points.

Input

terrainSamples(input: TerrainSamplesInput!)

Example

query TerrainSamples($input: TerrainSamplesInput!) {
  terrainSamples(input: $input) {
    count
    coveredCount
    zoom
    resolutionMeters
    samples {
      point
      elevation
      slope
      aspect
      aspectOctant
      steepnessBand
    }
  }
}

Response

TerrainSamplesResult returns count, coveredCount, zoom, resolutionMeters, and samples, one entry per requested location in the order you sent them.

terrainProfile

Readings along a line: the elevation profile of a geometry, as data.

Input

terrainProfile(input: TerrainProfileInput!)

Example

query TerrainProfile($input: TerrainProfileInput!) {
  terrainProfile(input: $input) {
    count
    coveredCount
    resolutionMeters
    samples {
      point
      distanceMeters
      elevation
      slope
    }
  }
}

Response

TerrainProfileResult has the same shape as TerrainSamplesResult, and its samples carry distanceMeters.

terrainGrid

Readings across an area, on a regular lattice.

Input

terrainGrid(input: TerrainGridInput!)

Example

query TerrainGrid($input: TerrainGridInput!) {
  terrainGrid(input: $input) {
    count
    coveredCount
    cols
    rows
    resolutionMeters
    cells {
      point
      elevation
      slope
      aspectOctant
    }
  }
}

Response

TerrainGridResult returns the samples as cells rather than samples, and echoes the cols and rows it laid them out on, so a flat list maps back onto the lattice by index.

Next steps