BAGIS Pourpoints

This repository contains the reference files for all the BAGIS pourpoint basins. Each file is a geojson representation of a BAGIS pourpoint object, with a point geometery and, optionally, a basin polyon.

The files have two formats:

• Point only:

  {
    "type": "Feature",
    "id": "008NG005:BC:USGS",
    "geometry" : {
      "type": "Point",
      "coordinates": [-115.416645907612,49.4166535142733]
    },
    "properties": {
      "name": "Kootenay River at Wardner",
      "source": "ref",
    }
  }
  

• Point with basin polygon:

  {
    "type": "GeometryCollection",
    "id": "10336715:NV:USGS",
    "geometries": [
      {
        "type": "Point",
    "coordinates": [-119.9079470066,39.1721247477916]
      },
      {
        "type": "MultiPolygon",
    "coordinates": [[[[-119.89934048816,39.1540244499329],...]]]
      }
    ],
    "properties": {
      "name": "Marlette Lake Inflow",
      "source" : "ref"
    }
  }
  

Note that both Polygon or MultiPolygon types are supported for basin area geometries.

How to use this repo

These files are intended to be used to seed CSAR BAGIS web project databases with the reference and user pourpoint records. For loading/updating a given project database with these fixtures, please consult that project's documentation.

Adding a new reference record

Records are easily exported from the BAGIS plugin, where applicable. Records can also be generated manually or with other tooling where required, simply follow the formatting detailed above.

Reference pourpoint records should have a source of ref and need to be named with their stationtriplet with the : characters converted to _ and the extension .geojson. For example, 06034700_MT_USGS.geojson. The station triplet should also be used for the id.

For new reference records place the geojson file in the reference directory.

Reference pourpoints need to be updated from the source ArcGIS feature services. After adding new records, run the script bin/update-from-feature-services.py, which pulls three feeds and iterates through all the reference pourpoint files:

• Base list (master_aoi_list_fs): drives which records exist and their properties. New points here are added to the reference set with a source of ref.
• Point locations (stations_FCST_ACTIVE): the source of truth for point coordinates. Where a triplet matches, the reference file's point geometry is overwritten from this service. Stations present here but absent from the base list are added as new reference records from this feed's (narrower) schema, with the base-only properties left null for later completion.
• Basin polygons (master_FCST_AOI_polygons): where a triplet matches, the reference file is enriched with the basin polygon (becoming a GeometryCollection). Any polygon with no matching pourpoint in either point feed is written to the unmatched directory for manual review.

Review all changes from the update script via git diff to ensure nothing unexpected has happened.

New point-only record from the base list

When running the update script, any new points on the base list will be added to the reference set with a source of ref.

Updating an existing record with a geometry

Simply overwrite the existing file per the "Adding a new record" above. If the new record does not have all the properties from the base list, the update from the base list will resolve that. Note that point coordinates and basin polygons are refreshed from their feature services on each run, so any manual geometry edits to records present in those services will be overwritten.

User pourpoints

For pourpoints added by user request that do not match stations in the base list, add them to the user directory. Ensure the file extension is .geojson and use the same format as detailed above. For the source property use user.

Pourpoint? A note on terminology

In fact, the terminology used for naming this repo is not really correct. It turns out we have two types of points:

• Pourpoint: the point through which BAGIS has calculated all basin outflow will pass
• Forecast point: the reference location of the station providing ground truth (typically a USGS streamflow gauge)

In theory these points will coincide in the same location. In practice, they tend to have some differences. Forecast point coordinates are rarely, if ever, located directly on the stream feature which they are to be measuing. This can be due to a number of factors, such as inaccurate coordinates or wide water bodies. The BAGIS tools snap the forecase point to the stream before calculating the basin, which gives the pourpoint.

The points in these files are mostly, if not completely, forecast points. The intended use-case at current for these files is cartographic, so the forecast point vs pourpoint difference is not particularly meaningful. As a result we have not attempted to reconcile that difference at this time.