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https://github.com/JuliaGeo/LibSpatialIndex.jl

A library for spatially indexing kD bounding box data (based on libspatialindex)
https://github.com/JuliaGeo/LibSpatialIndex.jl

geo geospatial gis julia libspatialindex r-tree spatial-index

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A library for spatially indexing kD bounding box data (based on libspatialindex)

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# LibSpatialIndex



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LibSpatialIndex.jl is a julia wrapper around the C API of [libspatialindex](https://github.com/libspatialindex/libspatialindex), for spatially indexing kD bounding box data.  The Julia library (JLL) package is produced by the script at https://github.com/JuliaPackaging/Yggdrasil/tree/master/L/LibSpatialIndex and the resulting binary artifact is downloaded from https://github.com/JuliaBinaryWrappers/LibSpatialIndex_jll.jl.



# Quick Guide



A new RTree with 2 dimensions can be created using this package as follows:



```julia

import LibSpatialIndex

rtree = LibSpatialIndex.RTree(2)

```



## Insertion



Items can be inserted using the `insert!` method, where:



```julia

LibSpatialIndex.insert!(rtree, 1, [0.0, 0.0], [1.0, 1.0])

LibSpatialIndex.insert!(rtree, 2, Extexts.Extent(X=(0.0, 2.0), (0.0, 2.0)))

```



inserts two items,



- the first with `id` 1, associated with the box specified by `[xmin=0.0,ymin=0.0]` and `[xmax=1.0,ymax=1.0]`.

- the second with `id` 2, associated with the box specified by `[xmin=0.0,ymin=0.0]` and `[xmax=2.0,ymax=2.0]`.



## Queries



Thereafter, you can perform queries on the `rtree` using either (i) `intersects(rtree, minvalues, maxvalues)`

for all items intersecting the box specified by `minvalues` and `maxvalues`, or (ii)

`knn(rtree, minvalues, maxvalues, k)` for the `k` nearest items in `rtree` to the box

specified by `minvalues` and `maxvalues`.



### Intersection



So for instance:



```julia

LibSpatialIndex.intersects(rtree, [0.0, 0.0], [1.0, 1.0])

LibSpatialIndex.intersects(rtree, Extents.extent(X=(0.0, 1.0), Y=(0.0, 1.0)))

```



will return the vector `[1, 2]` on the `rtree` constructed earlier, to indicate that items

with ids `1` and `2` intersects the box specified by `[xmin=0.0, ymin=0.0]` and `[xmax=1.0, ymax=1.0]`.



Any GeoInterface.jl or Extents.jl compatible object can be used directly instead

of defining the `Extent` manually - the extent will either be detected or calculated.



You can also perform queries on any individual GeoInterface.jl compatible point, so: 



```julia

LibSpatialIndex.intersects(rtree, (1.0, 1.0))

```



will return the ids `[1, 2]` in the `rtree` constructed earlier, and:



```julia

LibSpatialIndex.intersects(rtree, [2.0, 2.0])

```



will only return the vector `[2]`, because item 1 does not contain the point `[2.0, 2.0]`.



### k Nearest Neighbors



For `knn` queries:



```julia

LibSpatialIndex.knn(rtree, [2.0, 2.0], 1)

```



returns the vector `[2]` because the item with id `2` is closest to the point `[2.0, 2.0]`, and



```julia

sort(LibSpatialIndex.knn(rtree, [2.0, 2.0], 2))

```



returns the vector `[1, 2]`. If the value of `k` exceeds the number of items in the `rtree`,

then fewer than `k` items will be returned, so:



```julia

sort(SI.knn(rtree, [2.0, 2.0], 3))

```



will return the vector `[1, 2]`.