Spatially explicit capture-recapture (SECR) methods extend traditional
capture-recapture methods for estimating population density by using information contained in the location of traps. The The central feature of the
improvement is estimation from the locations of traps at which animals were
and were not captured to estimate of the distance over which animals are
susceptible to capture. We show that standard SECR models are a special case of a more general class of model in which animal detection is not certain, but some
information is available about the location of detected animals. The model class
accommodates a range of spatial data types and includes as a special case
mark-recapture distance sampling, where distances to detected animals are
recorded by multiple observers. Other examples of additional information
that can be included are bearing to detected animals, strength of acoustic
signals received from detected animals, and time of arrival of acoustic signals
at detectors. Errors in variables are easily incorporated. We illustrate the versatility of the model and method through a number of applications, in each case using real and simulated data, and comparing our results with those from previous studies where these are available.