xenial (1) r.li.daemon.1grass.gz

Support for landscape index calculations on raster

DESCRIPTION

       This  documentation  is focused on scientists and developers who wants to implement a new landscape index
       computation. Refer to the r.li modules overview and g.gui.rlisetup module for user-focused documentation.

       r.li.daemon provides support for landscape index calculations on raster maps. It hides the management  of
       areas,  defined using g.gui.rlisetup command. It is not used like a standalone program, but its functions
       are a library used by all r.li.[index] commands.
       This description is a tutorial for new index definition.
       The developer has only to focus on a unique area, like in mathematical definitions, and has to write a  C
       implementation of it.
       The  areas  are  defined  using  a struct called area_des and it members are explained in the source code
       (doxygen) documentation.

       To write a new index only two steps are needed:

       1      Define a function and insert its declaration on file index.h in r.li.daemon folder, which contains
              all index declarations. This function must be of this kind:
                      int index(int fd, char ** par, area_des ad, double * result)
              where:

           •   fd is the raster map descriptor

           •   par is a matrix for special parameter (like argv in main)

           •   ad is the area descriptor

           •   result is where to put the index calculation result
       This  function  has  to return 1 on success and 0 otherwise.  This function type is defined using typedef
       named rli_func.

       2      Create a main for command line arguments parsing, and call the function
                      int calculateIndex(char *file, rli_func *f,
                                         char **parameters, char *raster, char *output);
              from the r.li library, for starting raster analysis.
              It follows the meaning of parameters:

           •   file name of configuration file created using g.gui.rlisetup

           •   f pointer to index function defined above

           •   parameters pointer to index special parameters

           •   raster name of raster to use

           •   output output file name

       Compile it using a changed Makefile based on the file for r.li.patchdensity.

       Refer to the r.li library documentation in the source code and implementation of r.li modules for details
       and examples.

NOTES

       Using  GRASS  library  function  to  access  raster  rows  can  slow down moving windows execution. It is
       recommended to use
       RLI_get_cell_row(int, int, area_des)
       RLI_get_fcell_row(int, int, area_des)
       RLI_get_dcell_row(int, int, area_des)
       to use an ad hoc build memory management developed to speed up  the  system.   The  documentation  is  in
       doxygen files.

SEE ALSO

       old r.le manual
       r.li - package overview
       g.gui.rlisetup

REFERENCES

       McGarigal,  K.,  and  B.  J.  Marks.  1995.  FRAGSTATS:  spatial pattern analysis program for quantifying
       landscape structure. USDA For. Serv.  Gen. Tech. Rep. PNW-351. (PDF)

AUTHORS

       Claudio Porta and Lucio Davide Spano, students of Computer Science University of Pisa (Italy).
       Commission from Faunalia Pontedera (PI)
       Rewritten from "r.le.setup" by William L. Baker
       Various bug fixes by Markus Metz
       This program is free software under the GPL (>=v2) Read the  COPYING  file  that  comes  with  GRASS  for
       details.

       Last changed: $Date: 2015-04-09 17:19:11 +0200 (Thu, 09 Apr 2015) $

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