01 - Finding nodes with a bounding box

//Defining a bounding box using query settings [bbox:-25.38653, 130.99883, -25.31478, 131.08938]; node; //Defining a bounding box using a statement parameter // //TRYME #1 delete or comment out the previous two statement lines //and try running the following variation instead after first removing // the two "// characters so that the statement is not treated as a comment //node(-25.38653, 130.99883, -25.31478, 131.08938); //Defining a bounding box based on the map view in Overpass Turbo // //TRYME #2. Delete or comment out the previous lines, then //try running this variation. While the other versions use a fixed box, //this version tracks you as you pan and zoom over the map. Try running it to //confirm this for yourself //node({{bbox}}); out skel;

This query selects all of nodes that are within a bounding box.

A bounding box is a rectangle that defines a geographic area. In OverpassQL a bounding box is defined by four values. The first two define the south-west corner of the box. The second pair defines its north east corner.

There are two main ways to define a bounding box within an OverpassQL query.

This example defines a bounding box that applies to the whole query. This is achieved using a query setting called "bbox".

Query settings provide a way to control how the entire query runs. Query settings appear at the start of a query and are defined with square brackets: [].

Here we're using the bbox setting. As we'll see later, other settings let us choose different output formats and tweak timeouts.

In the bbox setting we're providing the coordinates for a bounding box. These particular coordinates (25.38653, 130.99883, -25.31478, 131.08938) define a rectangle that includes Uluṟu. The sandstone monolith in Uluṟu-Kata Tjuta National Park, Australia.

The second way to define a bounding box is as a parameter to a statement.

To test this out, run the query in Overpass Turbo, then follow the instructions in the TRYME #1 comment to see that the bounding box is applied.

If you define a bounding box using a fixed set of points, then the query will only ever use that geographic area. But sometimes you want to run a query over whatever section of the map you're currently looking at.

The Overpass Turbo IDE provides a third way to define a bounding box. But automatically inserting the coordinates for the current map view into your query. This is specified by including the "{{box}}" shortcut instead of the coordinates. Overpass Turbo will then adjust your query before its run.

This won't happen if you submit a query directly to the API. Its only a feature of the IDE. But helpful when you're writing queries interactively.

When should you use the different variations?

• if you're using the same bounding box across your query, use a query setting. It makes the query more readable
• if you need to apply a bounding box to a single statement, then define it as a filter
• if you're writing a query intended to be used interactively within Overpass Turbo then use {{bbox}}
• if you're querying the API directly, always submit queries using specific coordinates. {{bbox}} won't work

Source File	01-nodes.osm
Authors	Leigh Dodds