OpenStreetMap contributors (2023). Trinidad and Tobago Main Roads [gis dataset]. OpenStreetMap. last updated: 2026-10-19 (update frequency: As Needed). A line feature set for the primary and secondary roads of Trindad and Tobago sourced from OpenStreetMap. Key words: Trinidad and Tobago, Roads, primary, secondary, transportation Open Geospatial Consortium Standards:

dynamic vector tiles

Analytical Functions:

gdsc_get_attributes( table, lat, lng, identifier, normal )

ETL documentation

ETL for tt_roads

######### # GDSC ETL is performed in two steps: shell script to ETL data into postgres # and then additional transformations with SQL in postGIS (if needed). #### ######### # Step 1 - bash script (pseudo code) #### # create directory structure and move into it mkdir -p /data/tt_roads/download -p /data/tt_roads/etl chmod -R 777 /data/tt_roads cd /data/tt_roads # set update flag based on last update and update frequency do_update=0 if date() < last_update + update_frequency else do_update = 1 # download if update flag is set: if do_update == 1 then curl -o download/tt_roads.osm 'https://overpass-api.de/api/interpreter?data=way%5B%22highway%22~%22secondary|primary%22%5D(area:3600555717);(._;>;);out;' 2>&1 # load into postGIS with: ogr2ogr -lco GEOMETRY_NAME=geom -f PostgreSQL PG:"" download/tt_roads.osm echo success: tt_roads.osm loaded with ogr2ogr ######### # Step 2 - SQL script (pseudo code): #### # Select proper geometry into the named table psql -d $POSTGRES_DB -U $POSTGRES_USER -p $POSTGRES_PORT -h gdsc-postgis-node-g2ofyeqsuupixow7 -c " SELECT * INTO tt_roads FROM lines; DROP TABLE IF EXISTS lines; DROP TABLE IF EXISTS multilinestrings; DROP TABLE IF EXISTS multipolygons; DROP TABLE IF EXISTS other_relations; DROP TABLE IF EXISTS points;" # remove duplicate points and make geometries valid: UPDATE tt_roads SET geom=ST_MakeValid(ST_RemoveRepeatedPoints(geom)); # add local geometry column and reproject existing geometries into local EPSG: ALTER TABLE tt_roads DROP COLUMN IF EXISTS geom_local CASCADE; SELECT AddGeometryColumn ( 'tt_roads', 'geom_local', 8035, 'multilinestring', 2 ); UPDATE tt_roads SET geom_local=ST_MakeValid(ST_RemoveRepeatedPoints(ST_Transform(ST_Multi(geom),8035))); CREATE INDEX tt_roads_geom_local_idx ON tt_roads USING GIST (geom_local); NOTIFY pgrst, 'reload schema';