.TH sites.occur
.SH NAME
\fIsites.occur\fR \- Description of the site occurrence report produced
by \fIs.menu\fR.
.SH DESCRIPTION
This is a discussion of the site occurrence report produced by
.I s.menu.


.NF
.in -5
SAMPLE OUTPUT


                             SITE OCCURRENCE REPORT
                        Yakima Firing Center, Washington


Location:  yakima
Mapset:    sample
Site List: arch_erosion - archeology (34 sites)

Analysis Region:
                    north: 5199975.00
   west:  692975.00                       east:  737975.00
                    south: 5154975.00


============================================================================

Layer: arch_survey          Archeologic Survey Areas (arch_survey)

cells in analysis region:     810000
sites in analysis region:         34

                                                                     degrees
                             cells     %    expected actual   chi      of   
Site Characteristics         cover   cover   sites    sites  square  freedom
--------------------        ------- ------- -------- ------ -------- -------
(  0) No data                764310                      11               

(  1) Hartmann,phase 1        25821    56.5     19.2      6    9.088     1
(  2) Hartmann,phase 2        11032    24.1      8.2     14    4.084     1
(  3) Wapora,phase 3           8837    19.3      6.6      3    1.945     1
                            ------- ------- -------- ------ -------- -------
      Totals                  45690   100.0     34.0     23   15.117     2

============================================================================
.bp
.FI
.in +5
.SH EXPLANATION
The "Site Occurrence Report"
provides aggregate site information organized by
raster map layers.

The report header contains the following information:

.in +8
.ll -10
.ti -5
Location
.br
GRASS database location (e.g., yakima),

.ti -5
Mapset
.br
GRASS mapset (e.g., sample)

.ti -5
Analysis Region
.br
the rectangular area in which the
analysis was run, reflecting the
current geographic settings of the user's mapset.

.ti -5
Site List
.br
name and description of the site list used for the report
and the number of sites in the list.  See manual entry for
\fIs.menu\fR for more discussion about these site lists.

.in -8
.ll +10
The rest of the report is divided into reports for each
raster map layers specified by the user.
In this SAMPLE OUTPUT, only one map layer (arch_survey) was specified.

Certain information heads up each of these reports:

.in +8
.ll -10
.ti -5
layer
.br
identifies the raster map layer along with the map layer title.

.ti -5
cells in analysis region
.br
the size of the analysis region (in cells).


.ti -5
sites in analysis region
.br
the number of sites in the analysis region.


.bp
.in -8
.ll +10
For each map layer category which occurs in a cell falling
within the boundaries of the analysis region,
as well as totals for the map layer as a whole,
various statistics are presented:


.in +8
.ll -10
.ti -5
Site Characteristics
.br
These are the numbers (i.e., values)
and names (i.e., descriptions)
for each category (i.e., characteristic)
which occurs in the map layer.

.ti -5
cells cover
.br
the number of cells in the analysis region having the
category value (i.e., site characteristic).

.ti -5
% cover
.br
the predominance of the category within the analysis region.

.ti -5
expected sites
.br
the number of sites in the analysis region which would be
expected to be observed having the
category value if all sites were evenly
distributed by in the region.

.ti -5
actual sites
.br
the number of sites in the analysis region
which were occurred in cells having the category value.

.ti -5
chi square
.br
gives the user a statistical test of the hypothesis that
\'site distribution is dependent on environmental factors'.
For this hypothesis to be true,
the chi-square test must fail since we are
calculating expected sites according to the hypothesis that
\'sites are randomly distributed'.

.ti -5
degrees of freedom
.br
Number of degrees of freedom for the chi-square test.
Each category value will have 1 degree of freedom, and can be
tested alone.  The entire map layer will have 1 less degree of freedom
than the number of categories.
.in -8
.ll +10
.bp
.SH NOTE
Category zero (0) throughout GRASS represents "no data".
Therefore, it is reported,
but not included in the totals or in the computation
of the chi-square statistics.
.SH SEE ALSO
.I s.db.rim,
.I s.in.ascii,
.I s.menu,
.I s.out.ascii,
.I s.surf.idw,
.I sites.S,
.I sites.format,
.I sites.report