Distance Sampling Detection Function and Abundance Estimation

A simple way of fitting detection functions to distance sampling data for both line and point transects. Adjustment term selection, left and right truncation as well as monotonicity constraints and binning are supported. Abundance and density estimates can also be calculated (via a Horvitz-Thompson-like estimator) if survey area information is provided.


Distance -- A very simple interface to mrds.

News

Distance version 0.9.4

  • Object ID uniqueness stopped abundance estimation from working (since NA IDs were "not unique").
  • Check that areas are consistently entered. This was problematic when areas were not entered identically for each region, but unique was used to extract the region table. Thanks to Katy Echave for finding this bug!
  • Monotonicity constraints were not applied during automated model selection. Thanks to Tiago Marques for spotting this.
  • AIC selection of adjustment terms goes up to 5 terms by default, as in DISTANCE. Thanks to Eric Rexstad for suggesting this.

Distance version 0.9.3

  • Updated tests to work with new unique object ID code.
  • Liberally sprinkled tests with suppressMessages()

Distance version 0.9.2

  • Now warning when columns are correctly named but not in the correct case. Thanks to Richard Borthwick for reporting this bug.
  • Now checks that object IDs are unique. Thanks to Ricardo Lima & Francisco Azevedo for highlighting this issue.

Distance version 0.9.1

  • Models with both covariates and adjustment terms can actually be specified -- this was not fully implemented in previous version.
  • ds() now tells the user the models which is returned (rather than previously fitted model)
  • links to mrds documentation on optimisation issues

Distance version 0.9

  • Flat file support example, see ?flatfile
  • New data set: simulated minke whale data, see ?minke and ?flatfile for an example analysis
  • Models with both covariates and adjustment terms can be specified.
  • Default left truncation is now 0, default right truncation is now the largest observed distance or furthest bin end.

Distance version 0.8.1

  • another fix to binning (redundant code/inconsistent definition between docs and code). (Thanks to Jason Roberts for finding this.)
  • binning would fail if there were NA distances, which might occur when using the simplified data tables
  • check implemented to ensure that samples have consistent (i.e. the same) effort (Eric Rexstad found this bug)
  • clarification that stratification only occurs at the abundance/density estimation stage (dht), rather than at the detection function modelling stage (thanks to Filipe Dias for this suggestion)
  • Setting order=0 is equivalent to adjustment=NULL to specify a detection function without adjustments. (Eric Rexstad brought this to my attention.)

Distance version 0.8.0

  • new simplified table data format (see ?ds)
  • bug in binning from cutpoints (thanks to Colin Beale for finding this)
  • removed percentage truncation for binned data, as it doesn't really make sense

Distance version 0.7.4

  • new initial values argument

Distance version 0.7.3

  • remove annoying crash when mrds failed to fit a model
  • NB the optimiser underlying mrds (optimx) has changed, update both of these packages to avoid issues.

Distance version 0.7.2

  • message tells the user the model that was selected

Distance version 0.7.1

  • debugging options
  • bug fixes (see github for further details)
    • automatic generation of adjustments did not generate any for poly/herm.

Distance version 0.7

  • "width" is now default for scaling

Reference manual

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install.packages("Distance")

0.9.6 by Laura Marshall, 17 days ago


http://github.com/DistanceDevelopment/Distance/


Browse source code at https://github.com/cran/Distance


Authors: David Lawrence Miller


Documentation:   PDF Manual  


Task views: Analysis of Ecological and Environmental Data


GPL (>= 2) license


Depends on mrds

Suggests testthat


Suggested by dsm.


See at CRAN