Overpass Tutorial
- 00 - The Beginning
- 01 - Finding nodes with a bounding box
- 02 - Outputting data about nodes
- 03 - Filtering nodes that have a tag
- 04 - Find nodes by matching tags and their values
- 05 - Find nodes by applying multiple filters
- 06 - Extracting multiple sets of nodes
- 07 - Calculating differences between results
- 08 - Generating JSON output
- 09 - Generating CSV output
- 10 - The default set
- 11 - Querying a set
- 12 - Searching within a radius using around
- 13 - Using around to filter against a set of results
- 14 - Searching by polygon
- 15 - Finding ways
- 16 - Ways and their nodes
- 17 - Ways and their tags
- 18 - Combining node and way queries
- 19 - Finding ways from their nodes
- 20 - Finding relations
- 21 - Type agnostic queries (nwr)
- 22 - Areas
- 23 - Finding the areas enclosing a feature
- 24 - Find the area derived from a feature
- 25 - Areas via Nominatim search
- 26 - Timeouts and endpoints
10 - The default set
Overpass queries consist of statements that query the OSM database to build up a set of results which can be serialised into different output formats.
That set of results has a name. It's called _(underscore).
All of the queries we've written so far have implicitly worked with this result set.
Our node queries have added results to the _ set and the out statements
have used the default set to produce our output.
The query below makes this use of the default set more obvious by explicitly using it in the individual statements.
The results of a statement can be written to a named set using the -> operator.
As we'll see in the following examples it is possible to create, manipulate and produce output from multiple named sets of results.
| Source File | 10-the-default-set.osm |
| Authors |
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