I imported OpenStreetMap data through osm2pgsql into PgSQL (PostGIS) and I would like to get an SF object from the data containing all primary roads (geometry) within a an area (bbox) into R.
I got lost since I would like to have also relations and nodes and im not sure if only a query on planet_osm_roads will be sufficient and how the imported data structure is different to osm xml data im normaly working with. I understand it is probably a bit broader question but
I would appreciate a start so to say to understand the query language better.
This is my approach but sadly i get an error
conn <- RPostgreSQL::dbConnect("PostgreSQL", host = MYHOST,
dbname = "osm_data", user = "postgres", password = MYPASSWORD)
pgPostGIS(conn)
a<-pgGetGeom(conn, c("public", "planet_osm_roads"), geom = "way", gid = "osm_id",
other.cols = FALSE, clauses = "WHERE highway = 'primary' && ST_MakeEnvelope(11.2364353533134, 47.8050651144447, 11.8882527806375, 48.2423300001326)")
a<-st_as_sf(a)
This is an error i get:
Error in postgresqlExecStatement(conn, statement, ...) :
RS-DBI driver: (could not Retrieve the result : ERROR: syntax error at or near "ST_MakeEnvelope"
LINE 2: ...lic"."planet_osm_roads" WHERE "way" IS NOT NULL ST_MakeEnv...
^
)
Error in pgGetGeom(conn, c("public", "planet_osm_roads"), geom = "way", :
No geometries found.
In addition: Warning message:
In postgresqlQuickSQL(conn, statement, ...) :
Could not create execute: SELECT DISTINCT a.geo AS type
FROM (SELECT ST_GeometryType("way") as geo FROM "public"."planet_osm_roads" WHERE "way" IS NOT NULL ST_MakeEnvelope(11.2364353533134, 47.8050651144447, 11.8882527806375, 48.2423300001326)) a;
This is the db:
osm_data=# \d
List of relations
Schema | Name | Type | Owner
----------+--------------------+----------+----------
public | geography_columns | view | postgres
public | geometry_columns | view | postgres
public | planet_osm_line | table | postgres
public | planet_osm_nodes | table | postgres
public | planet_osm_point | table | postgres
public | planet_osm_polygon | table | postgres
public | planet_osm_rels | table | postgres
public | planet_osm_roads | table | postgres
public | planet_osm_ways | table | postgres
public | spatial_ref_sys | table | postgres
topology | layer | table | postgres
topology | topology | table | postgres
topology | topology_id_seq | sequence | postgres
schema_name table_name geom_column geometry_type type
1 public planet_osm_line way LINESTRING GEOMETRY
2 public planet_osm_point way POINT GEOMETRY
3 public planet_osm_polygon way GEOMETRY GEOMETRY
4 public planet_osm_roads way LINESTRING GEOMETRY
Table "public.planet_osm_roads"
Column | Type | Collation | Nullable | Default
--------------------+---------------------------+-----------+----------+---------
osm_id | bigint | | |
access | text | | |
addr:housename | text | | |
addr:housenumber | text | | |
addr:interpolation | text | | |
admin_level | text | | |
aerialway | text | | |
aeroway | text | | |
amenity | text | | |
area | text | | |
barrier | text | | |
bicycle | text | | |
brand | text | | |
bridge | text | | |
boundary | text | | |
building | text | | |
construction | text | | |
Your query looks just fine. Check the following example:
WITH planet_osm_roads (highway,way) AS (
VALUES
('primary','SRID=3857;POINT(1283861.57 6113504.88)'::geometry), --inside your bbox
('secondary','SRID=3857;POINT(1286919.06 6067184.04)'::geometry) --somewhere else ..
)
SELECT highway,ST_AsText(way)
FROM planet_osm_roads
WHERE
highway IN ('primary','secondary','tertiary') AND
planet_osm_roads.way && ST_Transform(
ST_MakeEnvelope(11.2364353533134,47.8050651144447,11.8882527806375,48.2423300001326, 4326),3857
);
highway | st_astext
---------+------------------------------
primary | POINT(1283861.57 6113504.88)
This image illustrates the BBOX and the points used in the example above
documentation
for more information on the bbox intersection operator &&
.However, there are a few things to consider.
ST_Contains
, consider simply using ST_DWithin
. It will basically does the same, but you only have to provide a reference point and the distance.highway
types in the table planet_osm_roads
and considering that your queries will always look for either primary
,secondary
or tertiary
highways, creating a partial index
could significantly improve performance. As the documentation says:A partial index is an index built over a subset of a table; the subset is defined by a conditional expression (called the predicate of the partial index). The index contains entries only for those table rows that satisfy the predicate. Partial indexes are a specialized feature, but there are several situations in which they are useful.
So try something like this:
CREATE INDEX idx_planet_osm_roads_way ON planet_osm_roads USING gist(way)
WHERE highway IN ('primary','secondary','tertiary');
And also highway
needs to be indexed. So try this ..
CREATE INDEX idx_planet_osm_roads_highway ON planet_osm_roads (highway);
.. or even another partial index, in case you can't delete the other data but you don't need it for anything:
CREATE INDEX idx_planet_osm_roads_highway ON planet_osm_roads (highway)
WHERE highway IN ('primary','secondary','tertiary');
You can always identify bottlenecks and check if the query planer is using your index with EXPLAIN
.
Further reading