OpenStreetMap contributors (2025). OSM Tanzania Populated Places [gis dataset]. OpenStreetMap. https://www.openstreetmap.org/. last updated: 0001-01-01 (update frequency: As Needed). A point feature set for the populated places in Tanzania sourced from OpenStreetMap with a query that includes Cities, Towns, Villages, and Hamlets. Key words: Tanzania, Populated Places, Cities, Towns, Villages, Hamlets Open Geospatial Consortium Standards: dynamic vector tiles | | WMS (coming soon) | WFS (coming soon) Analytical Functions: gdsc_get_attributes(tablename=tz_populated_places_osm,lat=25.718,lng=-80.279,identifier=name,normal='') ETL documentation

ETL for tz_populated_places_osm

######### # 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/tz_populated_places_osm/{download,etl} && cd /data/tz_populated_places_osm # 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/tz_populated_places_osm.osm 'https://overpass-api.de/api/interpreter?data=area%28id:3600195270%29-%3E.searchArea;node%5B%22place%22~%22city|town|village|hamlet%22%5D%28area.searchArea%29;%28._;%3E;%29;out;' # load into postGIS with: ogr2ogr -lco GEOMETRY_NAME=geom -f PostgreSQL PG:"" download/tz_populated_places_osm.osm ######### # Step 2 - SQL script (pseudo code): #### # Select proper geometry into the named table psql -d $POSTGRES_DB -U $POSTGRES_USER -p $POSTGRES_PORT -h None -c " SELECT * INTO tz_populated_places_osm FROM points; 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 tz_populated_places_osm SET geom=ST_MakeValid(ST_RemoveRepeatedPoints(geom)); # add local geometry column and reproject existing geometries into local EPSG: SELECT AddGeometryColumn ( 'tz_populated_places_osm', 'geom_local', 4326, 'point', 2 ); UPDATE tz_populated_places_osm SET geom_local=ST_MakeValid(ST_RemoveRepeatedPoints(ST_Transform(geom,4326))); CREATE INDEX tz_populated_places_osm_geom_local_idx ON tz_populated_places_osm USING GIST (geom_local); NOTIFY pgrst, 'reload schema'; # Move into corrrect directory and create derivative directory in data package on osgeo cd /data/tz_populated_places_osm/ mkdir -p derived # Create shapefile of table in derivate directory on osgeo ogr2ogr -f "ESRI Shapefile" -overwrite derived/tz_populated_places_osm.shp PG:"" tz_populated_places_osm # Create downloadable tarfile of shp in derivative directory on osgeo rm -f derived/tz_populated_places_osm.shp.tar.gz tar -czf derived/tz_populated_places_osm.shp.tar.gz meta_dcat_tz_populated_places_osm.json -C derived tz_populated_places_osm.shp tz_populated_places_osm.prj tz_populated_places_osm.shx tz_populated_places_osm.dbf # Move into correct directory cd /data/tz_populated_places_osm/