Contour Generator

Generates contour tiles in Mapbox Vector Tile (MVT) format from terrain raster-dem data using maplibre-contour. It allows maplibre-contour to work with PMTiles (local or HTTP) when the demUrl is prefixed with pmtiles:// and outputs to local MVT tiles.

This script outputs tile files in the <outputDir>/z/x/y.pbf format and generates a <outputDir>/metadata.json file. These files can be imported using mbutil. For example, to import the tiles into an mbtiles file using mbutil, the syntax would be: mb-util --image_format=pbf <outputDir> output.mbtiles.

Script Parameters

Generates contour tiles based on specified function and parameters.

Docker Usage: docker run --rm -v $(pwd):/data wifidb/contour-generator <function> [options]
Local Usage: node . <function> [options] NPM Globally Installed: contour-generator <function> [options]

Functions:

• pyramid: Generates contours for a parent tile and all child tiles up to a specified max zoom level.
• zoom: Generates a list of parent tiles at a specified zoom level, then runs pyramid on each of them in parallel.
• bbox: Generates a list of parent tiles that cover a bounding box, then runs pyramid on each of them in parallel.

General Options

• --demUrl <string>: The URL of the DEM source (e.g., pmtiles://<http or local file path> or a tile URL pattern like https://<zxyPattern>).
• --encoding <string>: The encoding of the source DEM tiles (e.g., 'terrarium', 'mapbox'). (default: mapbox)
• --sourceMaxZoom <number>: The maximum zoom level of the source DEM. (default: 8)
• --increment <number>: The contour increment value to extract. Use 0 for default thresholds.
• --outputMaxZoom <number>: The maximum zoom level of the output tile pyramid. (default: 8)
• --outputDir <string>: The output directory where tiles will be stored. (default: ./output)
• --processes <number>: The number of parallel processes to use. (default: 8)
• --blankTileNoDataValue <number>: The elevation value to use for blank tiles when a DEM tile is missing. (default: 0)
• --blankTileSize <number>: The pixel dimension of the tiles (e.g., 256 or 512). (default: 512)
• --blankTileFormat <string>: The image format for generated blank tiles ('png', 'webp', or 'jpeg'). This is used as a fallback if the source format cannot be determined. (default: png)
• -v, --verbose: Enable verbose output.
• -h, --help: Show this usage statement.

Function-Specific Options

For pyramid:

• --x <number>: The X coordinate of the parent tile. (Required)
• --y <number>: The Y coordinate of the parent tile. (Required)
• --z <number>: The Z coordinate of the parent tile. (Required)

For zoom:

• --outputMinZoom <number>: The minimum zoom level of the output tile pyramid. (default: 5)

For bbox:

• --minx <number>: The minimum X coordinate of the bounding box. (Required)
• --miny <number>: The minimum Y coordinate of the bounding box. (Required)
• --maxx <number>: The maximum X coordinate of the bounding box. (Required)
• --maxy <number>: The maximum Y coordinate of the bounding box. (Required)
• --outputMinZoom <number>: The minimum zoom level of the output tile pyramid. (default: 5)

Use with Docker

This image is published to Docker Hub as wifidb/contour-generator.

The docker image wifidb/contour-generator can be used for generating tiles in different ways.

Docker Examples:

pyramid function (using Docker w/pmtiles https source):

# View Help
 docker run -it -v $(pwd):/data wifidb/contour-generator pyramid --help

# Example
 docker run -it -v $(pwd):/data wifidb/contour-generator \
    pyramid \
    --z 9 \
    --x 272 \
    --y 179 \
    --demUrl "pmtiles://https://acalcutt.github.io/contour_generator/test_data/terrain-tiles.pmtiles" \
    --sourceMaxZoom 12 \
    --encoding mapbox \
    --increment 0 \
    --outputDir "/data/output_pyramid" \
    --outputMaxZoom 15 \
    -v
  
  # Test View Area #9/47.2542/11.5426

zoom function (using Docker w/pmtiles local source):

# View Help
 docker run -it -v $(pwd):/data wifidb/contour-generator zoom --help

# Downlad example test data into your local directory
 wget https://github.com/acalcutt/contour_generator/releases/download/test_data/JAXA_2024_terrainrgb_z0-Z7_webp.pmtiles

# Example
 docker run -it -v $(pwd):/data wifidb/contour-generator \
    zoom \
    --demUrl "pmtiles:///data/JAXA_2024_terrainrgb_z0-Z7_webp.pmtiles" \
    --outputDir "/data/output_zoom" \
    --sourceMaxZoom 7 \
    --encoding mapbox \
    --outputMinZoom 5 \
    --outputMaxZoom 7 \
    --increment 100 \
    --processes 8 \
    --blankTileNoDataValue 0 \
    --blankTileSize 512 \
    --blankTileFormat webp \
    -v
  
  # Test View Area #5/47.25/11.54
  # Note: some "No tile returned for" messages are normal with this JAXA dataset since there are areas without tiles

bbox function (using Docker w/zxyPattern source):

# View Help
 docker run -it -v $(pwd):/data wifidb/contour-generator bbox --help

# Example
 docker run -it -v $(pwd):/data wifidb/contour-generator \
    bbox \
    --minx -73.51 \
    --miny 41.23 \
    --maxx -69.93 \
    --maxy 42.88 \
    --demUrl "https://s3.amazonaws.com/elevation-tiles-prod/terrarium/{z}/{x}/{y}.png" \
    --sourceMaxZoom 15 \
    --encoding terrarium \
    --increment 50 \
    --outputMinZoom 5 \
    --outputMaxZoom 10 \
    --outputDir "/data/output_bbox" \
    -v

  # Test View Area #5/44.96/-73.35

Important Notes:

The -v $(pwd):/data part of the docker run command maps your local working directory $(pwd) to /data inside the Docker container. Therefore, your DEM file must be located in the /data directory inside of the docker image, and the output directory must also be in the /data directory.

Install Locally from git

git clone https://github.com/acalcutt/contour-generator.git
cd contour-generator
npm install

Local Examples:

pyramid function (Run Locally w/pmtiles https source):

# View Help
 node . pyramid --help

# Example
 node . pyramid \
  --z 9 \
  --x 272 \
  --y 179 \
  --demUrl "pmtiles://https://acalcutt.github.io/contour_generator/test_data/terrain-tiles.pmtiles" \
  --sourceMaxZoom 12 \
  --encoding mapbox \
  --increment 0 \
  --outputDir "./output_pyramid" \
  --outputMaxZoom 15 \
  -v

  #Test View Area #9/47.2542/11.5426

zoom function (Run Locally w/pmtiles local source):

# View Help
 node . zoom --help

# Downlad the test data into your local directory
 wget https://github.com/acalcutt/contour_generator/releases/download/test_data/JAXA_2024_terrainrgb_z0-Z7_webp.pmtiles

#Example
 node .  zoom \
  --demUrl "pmtiles://./JAXA_2024_terrainrgb_z0-Z7_webp.pmtiles" \
  --outputDir "./output_zoom" \
  --sourceMaxZoom 7 \
  --encoding mapbox \
  --outputMinZoom 5 \
  --outputMaxZoom 7 \
  --increment 100 \
  --processes 8 \
  -v

  # Test View Area #5/47.25/11.54 
  # Note: some "No tile returned for" messages are normal with this JAXA dataset since there are areas without tiles

bbox function (Run Locally w/zxyPattern source):

# View Help
 node . bbox --help

# Example
 node . bbox \
  --minx -73.51 \
  --miny 41.23 \
  --maxx -69.93 \
  --maxy 42.88 \
  --demUrl "https://s3.amazonaws.com/elevation-tiles-prod/terrarium/{z}/{x}/{y}.png" \
  --sourceMaxZoom 15 \
  --encoding terrarium \
  --increment 50 \
  --outputMinZoom 5 \
  --outputMaxZoom 10 \
  --outputDir "./output_bbox" \
  -v

  # Test View Area #5/44.96/-73.35

Test Data License Information

AWS mapzen terrarium tiles: https://registry.opendata.aws/terrain-tiles/ JAXA AW3D30: https://earth.jaxa.jp/en/data/policy/