Key to the successful application of remotely sensed data to real world problems is software that is capable of performing commonly used functions efficiently over large datasets, whilst being adaptable to new techniques. This paper presents an open source software library that was developed through research undertaken at Aberystwyth University for environmental remote sensing, particularly in relation to vegetation science. The software was designed to fill the gaps within existing software packages and to provide a platform to ease the implementation of new and innovative algorithms and data processing techniques. Users interact with the software through an XML script, where XML tags and attributes are used to parameterise the available commands, which have now grown to more than 300. A key feature of the XML interface is that command options are easily recognisable to the user because of their logical and descriptive names. Through the XML interface, processing chains and batch processing are supported. More recently a Python binding has been added to RSGISLib allowing individual XML commands to be called as Python functions. To date the Python binding has over 100 available functions, mainly concentrating on image utilities, segmentation, calibration and raster GIS. The software has been released under a GPL3 license and makes use of a number of other open source software libraries (e.g., GDAL/OGR), a user guide and the source code are available at http://www.rsgislib.org.