**-a**- Set for 8 cell-neighbors. 4 cell-neighbors are default
**-c**- Include cost of the path in the calculation of steps
**--overwrite**- Allow output files to overwrite existing files
**--help**- Print usage summary
**--verbose**- Verbose module output
**--quiet**- Quiet module output
**--ui**- Force launching GUI dialog

**input**=*name***[required]**- Name of input raster map
**suitability**=*string*- Name of the costmap with values from 0-100
**output**=*name***[required]**- Name for output raster map
**out_immi**=*string*- Name of the optional raster file for patch immigrants count
**keyval**=*integer***[required]**- Category value of the patches
**step_length**=*integer***[required]**- Length of a single step measured in pixels
**perception**=*integer*- Perception range
**multiplicator**=*float*- Attractivity of patches [1-inf]
**n**=*integer***[required]**- Number of individuals
**percent**=*float***[required]**- Percentage of individuals which must have arrived successfully to stop the model-run
**stats**=*string[,**string*,...]**[required]**- Statistical method to perform on the pathlengths of the individuals
- Options:
*average, variance, standard deviation, median, min, max* **dif_stats**=*string[,**string*,...]**[required]**- Statistical method to perform on the difference values
- Options:
*average, variance, standard deviation, median, min, max* **maxsteps**=*integer*- Maximum steps for each individual
**out_freq**=*integer*- Output an intermediate state of simulation each [out_freq] steps
**title**=*"phrase"*- Title for resultant raster map

This modules provides information about the importance of single
patches for maintaining the connectivity of individual fragments
derived of a landcover classification. Unlike *r.pi.energy.pr*
this module provides information about the differences in time from
emigration to immigration. The individual based dispersal model results
are based on the step length and range, the perception distance and the
attractivity to move towards patches.

The patch relevance concerning connectivity are based on patches of the
*landclass96* raster class 5 amd the time (amount of steps) from
emigration to immigration is computed. The step length is set to 5
pixel, the output statistics are set to *average* time and
*variance* of searchtime. For each patch 1000 individuals were
released and the model stopped when at least 80% of all individuals
sucessfully immigrated:

r.pi.searchtime.pr input=landclass96 output=searchtime_iter1 keyval=5 step_length=5 stats=average,variance percent=80 n=1000 dif_stats=average

r.pi.searchtime.pr input=landclass96 output=searchtime_iter1 keyval=5 step_length=5 stats=average,variance percent=80 n=1000 dif_stats=average perception=10

r.pi.searchtime.pr input=landclass96 output=searchtime_iter1 keyval=5 step_length=5 stats=average,variance percent=80 n=1000 dif_stats=average multiplicator=10

r.pi.searchtime.pr input=landclass96 output=searchtime_iter1 keyval=5 step_length=5 stats=average,variance percent=80 n=1000 dif_stats=average out_freq=10

r.pi.searchtime.pr input=landclass96 output=searchtime1 keyval=5 step_length=5 stats=average,variance percent=80 n=1000 dif_stats=average out_immi=immi_counts

# it is assumed that our species is a forest species and cannot move # through water, hence a cost of 100, does not like urban areas # (class: 6, cost: 10) but can disperse through shrubland (class 4, # cost=1) better than through grassland (class 3, cost: 2): r.mapcalc "suit_raster = if(landclass96==5,1,if(landclass96 == 1, 10, if (landclass96==3,2, if(landclass96==4,1,if(landclass96==6,100)))))" r.pi.searchtime.pr input=landclass96 output=searchtime1 keyval=5 step_length=5 stats=average,variance percent=80 n=1000 dif_stats=average suitability=suit_raster

Scientific concept: Dr. Martin Wegmann

Department of Remote Sensing

Remote Sensing and Biodiversity Unit

University of Wuerzburg, Germany

Port to GRASS GIS 7: Markus Metz

Available at: r.pi.searchtime.pr source code (history)

Latest change: Wed Feb 2 21:46:15 2022 in commit: 2e3dcb5eafe36d640aa68585be0192f07ca1eabb

Main index | Raster index | Topics index | Keywords index | Graphical index | Full index

© 2003-2022 GRASS Development Team, GRASS GIS 8.0.3dev Reference Manual