NAME
sites.occur - Description of the site occurrence
report produced by
s.menu.
DESCRIPTION
This is a discussion of the site occurrence report produced by
s.menu.
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
============================================================================
EXPLANATION
The "Site Occurrence Report" provides aggregate site
information organized by raster map layers.
The report header contains the following information:
- Location
- GRASS database location (e.g., yakima),
- Mapset
- GRASS mapset (e.g., sample)
- Analysis Region
- the rectangular area in which the
analysis was run, reflecting the
current geographic settings of the user's mapset.
- Site List
- name and description of the site list used for the report
and the number of sites in the list. See manual entry for
s.menu
for more discussion about these site lists.
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:
- layer
- identifies the raster map layer along with the map layer TITLE.
- cells in analysis region
- the size of the analysis region (in cells).
- sites in analysis region
- the number of sites in the analysis region.
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:
- Site Characteristics
- These are the numbers (i.e., values)
and names (i.e., descriptions)
for each category (i.e., characteristic)
which occurs in the map layer.
- cells cover
- the number of cells in the analysis region having the
category value (i.e., site characteristic).
- % cover
- the predominance of the category within the analysis region.
- expected sites
- 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.
- actual sites
- the number of sites in the analysis region
which were occurred in cells having the category value.
- chi square
- 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'.
- degrees of freedom
- 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.
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.
SEE ALSO
s.db.rim
s.in.ascii
s.menu
s.out.ascii
s.surf.idw
sites.S
sites.format
sites.report