Juan J. Collas
9pods
The Clipper library primarily performs the boolean clipping operations - intersection, union, difference & xor - on 2D polygons. It also performs polygon offsetting. The library handles complex (self-intersecting) polygons, polygons with holes and polygons with overlapping co-linear edges. Input polygons for clipping can use EvenOdd, NonZero, Positive and Negative filling modes. The clipping code is based on the Vatti clipping algorithm, and out performs other clipping libraries.
License: Boost
A JSON reader and writer which is super-efficient and usually runs circles around other JSON libraries. It's highly customizable to optimize for your particular project, and very lightweight. For Windows, OSX, or Linux. Works in any language.
License: Custom
PROJ.4 is in active use by GRASS GIS, MapServer, PostGIS, Thuban, OGDI, Mapnik, TopoCad, and OGRCoordinateTransformation as well as various other projects.
Since work started on the PROJ.4.4.x series of releases, various bug fixes have been incorporated, and the build system has been overhauled to use autoconf/libtool. Support has also been added for 3 and 7 parameter datum shifts, the PJ* structure now also carries datum information and PJ* can be considered a full coordinate system (geographic coordinate systems are also now supported with the +proj=latlong pseudo-projection). The new cs2cs program performs a similar function to the proj program, but transforming from any one coordinate system to another. The new pj_transform() is used to access the extended coordinate system to coordinate system transformation with datum shifting. Work is underway to improve ThreadSafety.
A mapping file (epsg) has also been introduced mapping most EPSG ( http://www.epsg.org/) coordinate systems to PROJ.4 format.
As of May 2008 PROJ.4 has become part of the MetaCRS project, a confederation of coordinate systems related projects and it is hoped MetaCRS will enter incubation as an OSGeo project.
License: MIT
If you don't know, you probably don't need this library. The Shapefile format is a working and interchange format promulagated by ESRI for simple vector data with attributes. An excellent white paper on the shapefile format is available from ESRI, but it is .pdf format, so you will need Adobe Acrobat to browse it.
The file format actually consists of three files.
XXX.shp - holds the actual vertices. XXX.shx - hold index data pointing to the structures in the .shp file. XXX.dbf - holds the attributes in xBase (dBase) format.
License: MIT
TinyXML2 is a simple, small, efficient, C++ XML parser that can be easily integrating into other programs.
License: zlib
WhirlyGlobe-Maply is a high performance geospatial display toolkit for iOS and Android. The iOS version supports big, complex apps like Dark Sky and National Geographic World Atlas, among others. Even so, it's easy to get started on your own project.
License: Apache 2
A new, smaller version of the WhirlyGlobe-Maply resources.
License: Apache 2