Distance is free software for the design and analysis of distance sampling surveys of wildlife population size or density. It has been downloaded by around 6000 people from over 100 countries.
Distance sampling methods are documented in the two standard texts: Introduction to Distance Sampling (Buckland et al., 2001) and Advanced Distance Sampling (Buckland et al., 2004).

Distance has a built-in geographic information system (GIS), which allows different survey designs to be laid out in a defined study area and various properties of the design tested. It also has a number of analysis engines that allow standard analyses of line or point transect data, as well as more advanced analyses such as multiple covariates distance sampling (MCDS) and mark-recapture distance sampling (MRDS, or double-platform analyses). The latter analysis engine is implemented as a library in the free statistical software R, and Distance seamlessly calls R to perform the analysis.

The software is continually under development, and more facilities are planned for future releases. If you are interested in sponsoring a particular development that would be of use to you, please contact the program authors.

WiSP is an R library of functions designed as a teaching tool to illustrate methods used to estimate the abundance of closed animal populations. It enables users to generate animal populations having realistically complex spatial and individual characteristics, to generate survey designs for a variety of survey techniques, to survey the populations and to estimate abundance.

WiSP can be downloaded from the Estimating Animal Abundance web site.