Getting information from vector datasets

Utility

gdal vector info

Getting vector layer names

# run from the workshop data directory

$ gdal vector info timisoara.osm.pbf --summary

Output:

INFO: Open of `timisoara.osm.pbf'
      using driver `OSM' successful.
1: points (Point)
2: lines (Line String)
3: multilinestrings (Multi Line String)
4: multipolygons (Multi Polygon)
5: other_relations (Geometry Collection)

Getting structure of vector layers

$ gdal vector info timisoara.osm.pbf

Output:

INFO: Open of `timisoara.osm.pbf'
      using driver `OSM' successful.

Layer name: points
Geometry: Point
Feature Count: -1
Layer Coordinate Reference System:
  - name: WGS 84
  - ID: EPSG:4326
  - type: Geographic 2D
Data axis to CRS axis mapping: 2,1
osm_id: String (0.0)
name: String (0.0)
barrier: String (0.0)
highway: String (0.0)
ref: String (0.0)
address: String (0.0)
is_in: String (0.0)
place: String (0.0)
man_made: String (0.0)
other_tags: String (0.0)

Layer name: lines
Geometry: Line String
Feature Count: -1
Layer Coordinate Reference System:
  - name: WGS 84
  - ID: EPSG:4326
  - type: Geographic 2D
Data axis to CRS axis mapping: 2,1
osm_id: String (0.0)
name: String (0.0)
highway: String (0.0)
waterway: String (0.0)
aerialway: String (0.0)
barrier: String (0.0)
man_made: String (0.0)
railway: String (0.0)
z_order: Integer (0.0)
other_tags: String (0.0)

Layer name: multilinestrings
Geometry: Multi Line String
Feature Count: -1
Layer Coordinate Reference System:
  - name: WGS 84
  - ID: EPSG:4326
  - type: Geographic 2D
Data axis to CRS axis mapping: 2,1
osm_id: String (0.0)
name: String (0.0)
type: String (0.0)
other_tags: String (0.0)

Layer name: multipolygons
Geometry: Multi Polygon
Feature Count: -1
Layer Coordinate Reference System:
  - name: WGS 84
  - ID: EPSG:4326
  - type: Geographic 2D
Data axis to CRS axis mapping: 2,1
osm_id: String (0.0)
osm_way_id: String (0.0)
name: String (0.0)
type: String (0.0)
aeroway: String (0.0)
amenity: String (0.0)
admin_level: String (0.0)
barrier: String (0.0)
boundary: String (0.0)
building: String (0.0)
craft: String (0.0)
geological: String (0.0)
historic: String (0.0)
land_area: String (0.0)
landuse: String (0.0)
leisure: String (0.0)
man_made: String (0.0)
military: String (0.0)
natural: String (0.0)
office: String (0.0)
place: String (0.0)
shop: String (0.0)
sport: String (0.0)
tourism: String (0.0)
other_tags: String (0.0)

Layer name: other_relations
Geometry: Geometry Collection
Feature Count: -1
Layer Coordinate Reference System:
  - name: WGS 84
  - ID: EPSG:4326
  - type: Geographic 2D
Data axis to CRS axis mapping: 2,1
osm_id: String (0.0)
name: String (0.0)
type: String (0.0)
other_tags: String (0.0)

Listing features

Listing all features from the points layer

$ gdal vector info timisoara.osm.pbf --input-layer points --features

Output:

INFO: Open of `timisoara.osm.pbf'
      using driver `OSM' successful.

Layer name: points
Geometry: Point
Feature Count: -1
Layer Coordinate Reference System:
  - name: WGS 84
  - ID: EPSG:4326
  - type: Geographic 2D
Data axis to CRS axis mapping: 2,1
osm_id: String (0.0)
name: String (0.0)
barrier: String (0.0)
highway: String (0.0)
ref: String (0.0)
address: String (0.0)
is_in: String (0.0)
place: String (0.0)
man_made: String (0.0)
other_tags: String (0.0)
OGRFeature(points):25478311
  osm_id (String) = 25478311
  highway (String) = traffic_signals
  POINT (21.2694902 45.7290217)

OGRFeature(points):25478391
  osm_id (String) = 25478391
  name (String) = Elbromplast
  other_tags (String) = "bus"=>"yes","public_transport"=>"stop_position"
  POINT (21.2698833 45.7331868)

[ ... snip ... ]

Applying an attribute filter, and limiting the output

You can apply an attribute filter by specifying a SQL WHERE filtering clause with the --where option. By default, this uses the OGR SQL dialect which is a subset of the full SQL-92 standard.

$ gdal vector info timisoara.osm.pbf --input-layer points --features --where "other_tags LIKE '%restaurant%'" --limit 5

Output:

INFO: Open of `timisoara.osm.pbf'
      using driver `OSM' successful.

Layer name: points
Geometry: Point
Feature Count: -1
Layer Coordinate Reference System:
  - name: WGS 84
  - ID: EPSG:4326
  - type: Geographic 2D
Data axis to CRS axis mapping: 2,1
osm_id: String (0.0)
name: String (0.0)
barrier: String (0.0)
highway: String (0.0)
ref: String (0.0)
address: String (0.0)
is_in: String (0.0)
place: String (0.0)
man_made: String (0.0)
other_tags: String (0.0)
OGRFeature(points):304555464
  osm_id (String) = 304555464
  name (String) = Stejarul
  other_tags (String) = "amenity"=>"restaurant"
  POINT (21.4248647 45.7521308)

OGRFeature(points):380526548
  osm_id (String) = 380526548
  name (String) = Restaurant Tinecz
  other_tags (String) = "addr:city"=>"Timișoara","addr:housenumber"=>"51","addr:street"=>"Calea Aradului","amenity"=>"restaurant","cuisine"=>"regional","opening_hours"=>"Mo-Su 11:00-23:00","phone"=>"0736 660 787","website"=>"https://www.restauranttinecz.ro/"
  POINT (21.2221875 45.7710081)

OGRFeature(points):380526549
  osm_id (String) = 380526549
  name (String) = Iris
  other_tags (String) = "amenity"=>"restaurant","cuisine"=>"regional"
  POINT (21.2147065 45.7746345)

OGRFeature(points):477200233
  osm_id (String) = 477200233
  name (String) = Pizzeria Rebecca
  other_tags (String) = "amenity"=>"restaurant"
  POINT (21.2240089 45.7754256)

OGRFeature(points):477234572
  osm_id (String) = 477234572
  name (String) = Pizzeria Amedeea
  other_tags (String) = "amenity"=>"restaurant"
  POINT (21.2310551 45.7757755)

JSON output / open options

A number of GDAL raster and vector drivers have "open options", which control how the driver behaves. They are documented in each driver's documentation page. For OSM, at https://gdal.org/en/stable/drivers/vector/osm.html#open-options

The other_tags field is exposed using the PostgreSQL HSTORE key/value data type which predates the introduction of JSON. But we may query it to be exposed as JSON with --open-option TAGS_FORMAT=JSON, and also request features to be exposed as GeoJSON with --format json.

$ gdal vector info timisoara.osm.pbf --input-layer points --features --where "other_tags LIKE '%restaurant%'" --limit 1 --format json --open-option TAGS_FORMAT=JSON

{
  "description":"timisoara.osm.pbf",
  "driverShortName":"OSM",
  "driverLongName":"OpenStreetMap XML and PBF",
  "layers":[
    {
      "name":"points",
      "metadata":{},
      "geometryFields":[
        {
          "name":"",
          "type":"Point",
          "nullable":true,
          "coordinateSystem":{
            "wkt":"GEOGCRS[\"WGS 84\",\n    DATUM[\"World Geodetic System 1984\",\n        ELLIPSOID[\"WGS 84\",6378137,298.257223563,\n            LENGTHUNIT[\"metre\",1]]],\n    PRIMEM[\"Greenwich\",0,\n        ANGLEUNIT[\"degree\",0.0174532925199433]],\n    CS[ellipsoidal,2],\n        AXIS[\"geodetic latitude (Lat)\",north,\n            ORDER[1],\n            ANGLEUNIT[\"degree\",0.0174532925199433]],\n        AXIS[\"geodetic longitude (Lon)\",east,\n            ORDER[2],\n            ANGLEUNIT[\"degree\",0.0174532925199433]],\n    ID[\"EPSG\",4326]]",
            "projjson":{
              "$schema":"https://proj.org/schemas/v0.7/projjson.schema.json",
              "type":"GeographicCRS",
              "name":"WGS 84",
              "datum":{
                "type":"GeodeticReferenceFrame",
                "name":"World Geodetic System 1984",
                "ellipsoid":{
                  "name":"WGS 84",
                  "semi_major_axis":6378137,
                  "inverse_flattening":298.257223563
                }
              },
              "coordinate_system":{
                "subtype":"ellipsoidal",
                "axis":[
                  {
                    "name":"Geodetic latitude",
                    "abbreviation":"Lat",
                    "direction":"north",
                    "unit":"degree"
                  },
                  {
                    "name":"Geodetic longitude",
                    "abbreviation":"Lon",
                    "direction":"east",
                    "unit":"degree"
                  }
                ]
              },
              "id":{
                "authority":"EPSG",
                "code":4326
              }
            },
            "dataAxisToSRSAxisMapping":[
              2,
              1
            ]
          }
        }
      ],
      "featureCount":-1,
      "fields":[
        {
          "name":"osm_id",
          "type":"String",
          "nullable":true,
          "uniqueConstraint":false
        },
        {
          "name":"name",
          "type":"String",
          "nullable":true,
          "uniqueConstraint":false
        },
        {
          "name":"barrier",
          "type":"String",
          "nullable":true,
          "uniqueConstraint":false
        },
        {
          "name":"highway",
          "type":"String",
          "nullable":true,
          "uniqueConstraint":false
        },
        {
          "name":"ref",
          "type":"String",
          "nullable":true,
          "uniqueConstraint":false
        },
        {
          "name":"address",
          "type":"String",
          "nullable":true,
          "uniqueConstraint":false
        },
        {
          "name":"is_in",
          "type":"String",
          "nullable":true,
          "uniqueConstraint":false
        },
        {
          "name":"place",
          "type":"String",
          "nullable":true,
          "uniqueConstraint":false
        },
        {
          "name":"man_made",
          "type":"String",
          "nullable":true,
          "uniqueConstraint":false
        },
        {
          "name":"other_tags",
          "type":"String",
          "subType":"JSON",
          "nullable":true,
          "uniqueConstraint":false
        }
      ],
      "features":[
        {
          "type":"Feature",
          "properties":{
            "osm_id":"304555464",
            "name":"Stejarul",
            "other_tags":{
              "amenity":"restaurant"
            }
          },
          "fid":304555464,
          "geometry":{
            "type":"Point",
            "coordinates":[
              21.4248647,
              45.7521308
            ]
          }
        }
      ]
    }
  ],
  "metadata":{},
  "domains":{}
}

Exercise

Find the 5 closest bars from Timișoara center (45.7558° N, 21.2322° E)

(hint)

Hint

  • use option --sql

  • use SQLite dialect (--dialect SQLite)

  • the name of the geometry column when using a non-RDBMS data set, such as OSM, and with SQLite dialect, is geometry

  • use Spatialite ST_Point function

  • use Spatialite ST_Distance function

==> Exercise solution for vector info.