QWC Elevation Service

Returns elevations.

Configuration

The static config files are stored as JSON files in $CONFIG_PATH with subdirectories for each tenant, e.g. $CONFIG_PATH/default/*.json. The default tenant name is default.

Elevation Service config

• JSON schema
• File location: $CONFIG_PATH/<tenant>/elevationConfig.json

Example:

{
  "$schema": "https://raw.githubusercontent.com/qwc-services/qwc-elevation-service/master/schemas/qwc-elevation-service.json",
  "service": "elevation",
  "config": {
    "elevation_dataset": "/vsicurl/https://data.sourcepole.com/srtm_1km_3857.tif"
  }
}

Environment variables

Config options in the config file can be overridden by equivalent uppercase environment variables.

Variable	Description
ELEVATION_DATASET	path/to/dtm.tif

Usage

Run as

python src/server.py

Requires GDAL Python bindings. python-gdal or python3-gdal packages on Debian/Ubuntu (Note: virtualenv creation requires --system-site-packages option).

API:

• Runs by default on http://localhost:5002
• GET: /getelevation?pos=<pos>&crs=<crs>
  • pos: the query position, as x,y
  • crs: the crs of the query position
  • output: a json document with the elevation in meters: {elevation: h}
• POST: /getheightprofile

  • payload: a json document as follows:

    {
        coordinates: [[x1,y1],[x2,y2],...],
        distances: [<dist_p1_p2>, <dist_p2_p3>, ...],
        projection: <EPSG:XXXX, projection of coordinates>,
        samples: <number of height samples to return>
    }
    

  • output: a json document with heights in meters: {elevations: [h1, h2, ...]}

Docker usage

The docker image can be run with the following command:

docker run -p 5002:9090 sourcepole/qwc-elevation-service

docker parameters	Description
-p 5002:9090	Bind port 5002 on the host machine