dst.source

DESCRIPTION

This program is used to define sources of evidence in a Dempster-Shafer knowledge base file. The knowledge base file is an XML format ASCII file which resides in its own 'DST' element inside the user's current mapset. Such a file is necessary to perform Dempster-Shafer Theory (DST) calculations using dst.combine . If you do not know what DST is or why you would need this program, please refer to the dst.combine command's manpage for an introduction.

Although the knowlegde base file can theoretically be edited with any ASCII editor, it is highly recommended to always use dst.source to make changes regarding sources of evidence. This ensures that the mathematical structure of the model layout will remain intact.

The dst.source command allows the user to define sources of evidence in a knowledge base file. This is the last step in preparing data for a DST analysis. To get an overview of the DST model structure and the defined sources of evidence at any time, use the dst.view command. Knowledge base files themselves can be listed, created, deleted and renamed using a special set of commands.

Since hypotheses can be defined and evidences attached to them using dst.update , it may seem unnecessary to define these relations again as 'sources of evidence'. However, the information structure created by dst.update is not necessarily unambiguous. There are no restrictions on the order in which evidences are attached and some hypotheses may be associated with more evidences than others. This means that it is not always clear which evidences have to be combined in one run of dst.combine and therefore another step is necessary. Defining sources of evidence ensures that one input to dst.combine will always consist of exactly one evidence for each hypothesis in the frame of reference and that BPA values relating to that hypothesis will not be accidentally combined with hypotheses from another source.

Parameters

file=name: Name of DST knowledge base file to modify. You can get a listing of DST knowledge base files in your current mapset by invoking dst.list .
add=name: Adds a source of evidence 'name' to the knowledge base. Naming conventions follow the same rules as filenames.
del=name: Deletes the evidence source 'name' from the knowledge base file.
ren=name: Renames evidence source 'name'. New name must be specified using the new=[name] parameter (see below).
new=name: Specifies a new name for renaming a source of evidence.
const=value: Assigns constant evidence to a source of evidence. The hypothesis (or set of hypotheses) to which this evidence relates must be specified using the hypothesis=[name] parameter. The target source must be specified using the source=[name] parameter.
rast=name: Assigns raster map evidence to a source of evidence.
vect=name: Assigns vector map evidence to a source of evidence.
clean=name: Removes all assignments to a source of evidence from a hypothesis (specified using hypothesis=[name]).
prune=name: Removes assignments to a source of evidence from one or all hypotheses. The type(s) of evidence (const,rast,vect) to un-assign can be specified using type=[name].
source=name: Specifies source of evidence to operate on. Case matters!
hypothesis=name: Specifies hypothesis to operate on. Note that order matters when refering to hypotheses sets: 'a,c' may exist, but 'c,a' not!
type=name: Type of evidence to un-assign (use in conjunction with prune=[hyp]). Possible options are const,rast,vect,*.

DESCRIPTION

Parameters

USAGE

Notes

SEE ALSO

AUTHOR