Spatial4n is a general purpose spatial / geospatial library for .NET, a direct port of the spatial4j Java library. Its core capabilities are:
- To provide common shapes that can be used in Euclidean and geodesic world models.
- To provide distance calculations and other math.
- To read and write shapes from formats like WKT.
When working with grid square indexing schemes, you will likely to find something especially useful in Spatial4n.
The main part of Spatial4n is its collection of shapes. Shapes in Spatial4n have these features:
- Compute its lat-lon bounding box.
- Compute an area. For some shapes its more of an estimate.
- Compute if it contains a provided point.
- Compute the relationship to a lat-lon rectangle. Relationships are:
Contains,Within,Disjoint,Intersects. Note that Spatial4n doesn't have a notion of "touching".
Spatial4n has a variety of shapes that operate in Euclidean-space -- i.e. a flat 2D plane. Most shapes are augmented to support a wrap-around at X -180/+180 for compatibility with latitude & longitudes, which is effectively a cylindrical model. But the real bonus is its circle (i.e. point-radius shape that can operate on a surface-of-a-sphere model. See below for further info. The term "geodetic" or "geodesic" or "geo" is used here as synonymous with that model but technically those words have a more broad meaning.
| Shape | Euclidean | Cylindrical | Spherical |
|---|---|---|---|
| Point | Y | Y | Y |
| Rectangle | Y | Y | Y |
| Circle | Y | N | Y |
| LineString | Y | N | N |
| Buffered L/S | Y | N | N |
| Polygon | Y | Y | N |
| ShapeCollection | Y | Y | Y |
- The Rectangle shape exists in the spherical model as a lat-lon rectangle, which basically means it's math is no different than cylindrical.
- Polygons don't support pole-wrap (sorry, no Antarctica polygon); just dateline-cross. Polygons are supported by wrapping NTS's
Geometry, which is to say that most of the fundamental logic for that shape is implemented by NTS.
- Read and write Shapes as WKT. Include the ENVELOPE extension from CQL, plus a Spatial4n custom BUFFER operation. Buffering a point gets you a Circle.
- 3 great-circle distance calculators: Law of Cosines, Haversine, Vincenty
Currently, the best sources of documentation are the Spatial4j javadocs and the Spatial4j Getting Started section.
To build the project from source, see the Building and Testing documentation.
If you find this library to be useful, please star us on GitHub and consider a financial sponsorship so we can continue bringing you great free tools like this one.