A C library for raster data including scientific and geophysical applications.

Welcome to the Gridfour software project's port to the C programming language. We are just getting started and aspects of this project are still in flux. Currently, we are focused on a C-langage implementation of the GVRS API.

The Gridfour Virtual Raster Store (GVRS, pronounced "givers") is a file-backed system that provides memory-efficient access to large and very large raster (grid) data sets. GVRS was created with three main purposes in mind:

1. Authoring Data: For applications that produce data sets, GVRS provides a high-performance virtual management system for handling content. Applications may store their final results in persisent GVRS files, or transcribe them to conventional formats (NetCDF, HDF5, TIFF and GeoTIFF, etc.).

2. Experiments in Data Compression: GVRS provides a convenient testbed for developers who are exploring new ways of performing data compression for raster data sources.

3. Distribution: GVRS provides a light-weight API and data format suitable for distributing data to other systems. GVRS was originally conceived as a way of providing environment data for small systems, single-board computers, and platforms such as Autonomous Underwater Vehicles. But it is a feasible solution for many other use cases.

The original Gridfour project was implemented in Java. More information about the original implementation is available at the Gridfour Software Project.

Currently, we have completed a read-only version of GVRS that runs under Windows and Linux. A cmake file is available for building the GVRS library. We are working on a series of how-to articles on our GridfourC wiki. Got something you'd like to learn more about? Let us know.

We are now turning our attention to implementing the ability for the C API to write data to a GVRS data store. The new GvrsBuilder functions provide a partial implementation of the ability to write files. Currently, they are limited to non-compressed formats and do not yet support metadata.
When that task is complete, the GVRS C API will be fully functional.

We are also in the process of adding doxygen-style documentation to our primary header files.

Please see our Wiki page for more information on the C API.

For the Gridfour project in general, we have two main documentation pages:

1. The Gridfour Project Notes give information on the underlying concepts and algorithms used by this project. The Notes page isn't just about Gridfour. It covers ideas and topics related to raster data processing in general.

2. The Gridfour Wiki gives lots of helpful information on using Gridfour software including our Gridfour Virtual Raster Store (GVRS). It also gives information about our project goals and roadmap.