This is a portolan catalog version of https://developer.trimet.org/gis/ - taking the static data layers there and making them fully cloud-native and interactive.
TriMet district boundary. 1 Polygon features, WGS84, one GeoParquet file of 88.5 KB in 1 row group(s).
Reads stream over HTTP range requests — query in place, do not download. The file
is Hilbert-ordered and carries a GeoParquet 1.1 bbox covering column, so a
spatial filter on geometry_bbox prunes row groups from metadata alone. Note
the column name: GDAL writes the covering as <geometry column>_bbox, so it is
geometry_bbox here, not bbox.
The recipes below use bare relative paths ('district-boundary/district-boundary.parquet') for
readability. Prefix them with https://data.source.coop/cholmes/trimet/ to run remotely.
Other formats: district-boundary.pmtiles for map display (layer name district-boundary), and TriMet's
original Shapefile and KML, linked from collection.json as source_shapefile
and source_kml.
The GeoParquet is in EPSG:2913 — NAD83(HARN) / Oregon North, international feet — which is what TriMet surveys and publishes in. It is deliberately not reprojected. Only the PMTiles are in WGS84, because vector tiles are Web Mercator by definition.
The practical consequence is a good one: measurements just work, in feet.
Useful conversions: × 0.3048 for metres, ÷ 5280 for miles, ÷ 43560 for acres, ÷ 27878400 for square miles. 400 m is 1312.34 ft, a quarter mile is 1320 ft.
Two things to watch:
GeoJSON consumers — needs a transform first.always_xy := true when you do transform. Without it DuckDB honours
EPSG:4326's authority-declared latitude-first axis order and every result
comes back Infinity:The bbox covering column is in the same feet, so a spatial filter written
against it uses projected coordinates, not degrees. The collection's STAC
extent stays in WGS84, because STAC requires that regardless of the data's own
CRS.
Nothing here carries a pre-computed length or area except the district boundary,
which has TriMet's own area_sq_mi and acres.
TriMet's metadata page documents AREA_SQ_MI and ACRES as Float, length 13.
In the actual DBF they are integers, and this catalog carries them through as
int64: 533 and 341554 exactly. If you need sub-square-mile precision, compute
it from the geometry — see the CRS section — rather than trusting these to be
rounded floats.
The file holds a single polygon with a few thousand vertices. Row-group pruning does nothing here. For repeated point-in-polygon tests, read the geometry once into a variable rather than re-scanning the file per query.
ST_GeometryType returns POLYGON. There are no islands or detached parts, so
you can use it directly in ST_Contains / ST_Within without dumping parts.
stops — the service the district exists to deliverroutes — alignments, a few of which run beyond the district edgeTriMet publishes this as tm_boundary at
developer.trimet.org/gis, last updated
January 09, 2013. Every column description in collection.json
comes from TriMet's metadata page — that
page, not this catalog, is the authority on what a field means.
Conversion: ogr2ogr -f Parquet -t_srs EPSG:4326 -lco COMPRESSION=ZSTD -lco SORT_BY_BBOX=YES -lco WRITE_COVERING_BBOX=YES, then tippecanoe with -r1 --no-feature-limit so no feature is dropped at any zoom. See
tools/convert.py.
TriMet distributes these datasets free of charge, but the terms of use do not
grant redistribution rights. Section 4 of TriMet's
Terms of Use reserves
reproduction, modification, distribution and republication of site Content
without written consent; the redistribution license in section 5 covers the Web
Services API, not these GIS downloads. The collections therefore declare
"license": "other" with a link to those terms, rather than claiming an open
license the source does not offer.
Practically: use the data, and contact gis@trimet.org before redistributing it or building a product on it. If you need transit data under clear open terms, TriMet's GTFS feed is the better starting point.