The Geospatial Data Abstraction Library (GDAL) is a unifying C/C++ API for accessing raster geospatial data, and currently includes formats like GeoTIFF, Erdas Imagine, Arc/Info Binary, CEOS, DTED, GXF, and SDTS. It is intended to provide efficient access, suitable for use in viewer applications, and also attempts to preserve coordinate systems and metadata. Python, C, and C++ interfaces are available.
Shapefile C Library is a C library for reading and writing ESRI Shapefiles and their related DBF files. All geometry types are supported, with robust DBF support. Shapelib is widely used for commercial and free projects. Shapelib includes command line utilities for dumping, subsetting, clipping, shifting, scaling, and reprojecting shapefiles.
GraphicsMagick is a robust collection of tools and libraries which support reading, writing, and manipulating an image in over 90 major formats including popular formats like DPX, DICOM, BMP, GIF, JPEG, JPEG-2000, PDF, PNG, PNM, SVG, and TIFF. A high-quality 2D renderer is included, which provides a subset of SVG capabilities. C, C++, Perl, Tcl, and Ruby are supported. Originally based on ImageMagick, GraphicsMagick focuses on performance, minimizing bugs, and providing stable APIs and ABIs. It runs on all modern variants of Unix, Windows, and Mac OS X.
exrtools is a set of simple command line utilities for manipulating high dynamic range images in OpenEXR format. It was developed to help experiment with batch processing of HDR images for tone mapping. Each application is small and reasonably self-contained so that the source code may be of most value to others.