build-contours

Optionally reprojects a LAS/LAZ point cloud, then extracts elevation contour lines and packages them as web-ready vector tiles. BUILD_CONTOURS rasterizes the cloud into a DSM, smooths it to suppress noise, runs gdal_contour to extract isolines, classifies them as major/minor, applies Chaikin corner-cutting for smooth curves, and exports to both MBTiles and PMTiles v3 — each containing a contours layer with elev and type (major/minor) attributes. DATASET_INFO runs in parallel to capture point cloud statistics. Fires a webhook on completion.

Recipe name: build-contoursVersion: 2.0.0Ordo ID: 43Reprojection: Optional (passthrough when source_epsg equals target_epsg or either is absent) Output formats: MBTiles (vector), PMTiles v3 (vector)

Steps

Step	Type	Runs
`reproject`	`REPROJECT_LAS`	First
`build_contours`	`BUILD_CONTOURS`	After `reproject`
`dataset_info`	`DATASET_INFO`	Parallel with `build_contours` (both after `reproject`)
`call_webhook`	`CALL_WEBHOOK`	`on_exit`

Recipe (v2.0.0 snapshot)

json

{
  "name": "build-contours",
  "version": "2.0.0",
  "definition": {
    "recipe": [
      {
        "id": "reproject",
        "type": "REPROJECT_LAS",
        "inputs":  { "input_las": "job:input_las" },
        "outputs": { "output_las": "step:reproject.output_las" },
        "param_keys": ["source_epsg", "target_epsg"]
      },
      {
        "id": "build_contours",
        "type": "BUILD_CONTOURS",
        "inputs":  { "input_las": "step:reproject.output_las" },
        "outputs": {
          "contours_mbtiles": "step:build_contours.contours_mbtiles",
          "contours_pmtiles": "step:build_contours.contours_pmtiles"
        },
        "param_keys": ["resolution", "output_type", "smoothing_factor", "contour_interval", "major_interval_multiplier", "simplify_tolerance", "chaikin_iterations"]
      },
      {
        "id": "dataset_info",
        "type": "DATASET_INFO",
        "inputs":  { "input_las": "step:reproject.output_las" },
        "outputs": { "metadata": "step:dataset_info.metadata" }
      }
    ],
    "on_exit": {
      "id": "call_webhook",
      "type": "CALL_WEBHOOK",
      "inputs": { "waits_for": "step:dataset_info.metadata" },
      "param_keys": ["webhook_url"]
    }
  }
}

Submitting a job

bash

curl -X POST https://dev.mapprism.com/ordo/jobs \
  -H "Authorization: Bearer <API_TOKEN>" \
  -H "Content-Type: application/json" \
  -d '{
    "recipe_id": 43,
    "inputs": {
      "job:input_las": {
        "type": "las",
        "uri": "development/survey/dataset.las",
        "hash": "abc123"
      }
    },
    "params": {
      "reproject": {
        "source_epsg": "EPSG:2271",
        "target_epsg": "EPSG:3857"
      },
      "build_contours": {
        "resolution": 1,
        "output_type": "mean",
        "smoothing_factor": 5,
        "contour_interval": 5,
        "major_interval_multiplier": 5,
        "simplify_tolerance": 1,
        "chaikin_iterations": 3
      },
      "call_webhook": {
        "webhook_url": "https://myapp.example.com/hooks/done"
      }
    },
    "outputs": {
      "step:build_contours.contours_mbtiles": {
        "path": "development/results/survey/contours.mbtiles"
      },
      "step:build_contours.contours_pmtiles": {
        "path": "development/results/survey/contours.pmtiles"
      },
      "step:dataset_info.metadata": {
        "path": "development/results/survey/metadata.json"
      }
    }
  }'

Poll for status:

bash

curl https://dev.mapprism.com/ordo/jobs/<job_id> \
  -H "Authorization: Bearer <API_TOKEN>"

Units note: BUILD_CONTOURS defaults are tuned for US survey feet (contour_interval: 5, resolution: 1). Adjust these values for metric datasets.

Required inputs

Artifact key	Type	Description
`job:input_las`	`las`	Source LAS/LAZ point cloud

Required params

Step	Param	Default	Description
`reproject`	`source_epsg`	—	Source CRS (e.g. `"EPSG:2271"`)
`reproject`	`target_epsg`	—	Target CRS (e.g. `"EPSG:3857"`)
`build_contours`	`resolution`	`1`	DSM raster cell size in CRS units
`build_contours`	`output_type`	`"mean"`	DSM height aggregation per cell: `mean`, `min`, `max`, `idw`, `count`, `stdev`, `all`
`build_contours`	`smoothing_factor`	`5`	DSM downsampled to `resolution × smoothing_factor` before contouring — higher values produce smoother contours
`build_contours`	`contour_interval`	`5`	Elevation interval between contour lines in CRS units
`build_contours`	`major_interval_multiplier`	`5`	Every Nth contour is classified as major
`build_contours`	`simplify_tolerance`	`1`	`ogr2ogr -simplify` tolerance in CRS units
`build_contours`	`chaikin_iterations`	`3`	Number of Chaikin corner-cutting passes
`call_webhook`	`webhook_url`	—	URL to POST the job result to

See BUILD_CONTOURS for full parameter details.

Producible outputs

Artifact	Type	Description
`step:build_contours.contours_mbtiles`	`mbtiles`	Vector tile package (MBTiles) — `contours` layer with `elev` and `type`
`step:build_contours.contours_pmtiles`	`pmtiles`	Vector tile package (PMTiles v3) — `contours` layer with `elev` and `type`
`step:dataset_info.metadata`	`json`	PDAL metadata report

build-contours ​

Steps ​

Recipe (v2.0.0 snapshot) ​

Submitting a job ​

Required inputs ​

Required params ​