Provided by: grass-doc_6.4.3-3_all 
NAME
r.coin - Tabulates the mutual occurrence (coincidence) of categories for two raster map
layers.
KEYWORDS
raster, statistics
SYNOPSIS
r.coin
r.coin help
r.coin [-w] map1=string map2=string units=string [--verbose] [--quiet]
Flags:
-w
Wide report, 132 columns (default: 80)
--verbose
Verbose module output
--quiet
Quiet module output
Parameters:
map1=string
Name of first raster map
map2=string
Name of second raster map
units=string
Unit of measure
c(ells), p(ercent), x(percent of category [column]), y(percent of category [row]),
a(cres), h(ectares), k(square kilometers), m(square miles)
Options: c,p,x,y,a,h,k,m
DESCRIPTION
r.coin tabulates the mutual occurrence of two raster map layers' categories with respect
to one another. This analysis program respects the current geographic region and mask
settings.
r.coin tabulates the coincidence of category values among the two map layers and prepares
the basic table from which the report is to be created. This tabulation is followed by an
indication of how long the coincidence table will be. If the table is extremely long, the
user may decide that viewing it is not so important after all, and may cancel the request
at this point. Assuming the user continues, r.coin then allows the user to choose one of
eight units of measure in which the report results can be given. These units are:
c
cells
p
percent cover of region
x
percent of category (column)
y
percent of category (row)
a
acres
h
hectares
k
square kilometers
m
square miles
Note that three of these options give results as percentage values: "p" is based on the
grand total number of cells; "x" is based on only column totals; and "y" is based on only
row totals. Only one unit of measure can be selected per report output. Type in just one
of the letters designating a unit of measure followed by a for review. After reviewing
the report on the screen, the user is given several options. The report may be saved to a
file and/or sent to a printer. If printed, it may be printed with either 80 or 132
columns. Finally, the user is given the option to rerun the coincidence tabulation using
a different unit of measurement.
NOTES
It is not a good idea to run r.coin on a map layer which has a monstrous number of
categories (e.g., unreclassed elevation). Because r.coin reports information for each and
every category, it is better to reclassify those categories (using r.reclass) into a more
manageable number prior to running r.coin on the reclassed raster map layer.
EXAMPLE
Below is a sample of tabular output produced by r.coin. Here, map output is stated in
units of square miles. The report tabulates the coincidence of the Spearfish sample
database's owner and road raster map layers' categories. The owner categories in this
case refer to whether the land is in private hands (category 1) or is owned by the U.S.
Forest Service (category 2). The roads map layer categories refer to various types of
roads (with the exception of category value "0", which indicates "no data"; i.e., map
locations at which no roads exist). r.coin does not report category labels. The user
should run r.report or r.category to obtain this information.
The body of the report is arranged in panels. The map layer with the most categories is
arranged along the vertical axis of the table; the other, along the horizontal axis. Each
panel has a maximum of 5 categories (9 if printed) across the top. In addition, the last
two columns reflect a cross total of each column for each row. All of the categories of
the map layer arranged along the vertical axis are included in each panel. There is a
total at the bottom of each column representing the sum of all the rows in that column. A
second total represents the sum of all the non-zero category rows. A cross total (Table
Row Total) of all columns for each row appears in a separate panel.
Note how the following information may be obtained from the sample report.
In the Spearfish data base, in area not owned by the Forest Service, there are 50.63
square miles of land not used for roads. Roads make up 9.27 square miles of land in this
area.
Of the total 102.70 square miles in Spearfish, 42.80 square miles is owned by the Forest
Service.
In total, there are 14.58 square miles of roads.
There are more category 2 roads outside Forest Service land (2.92 mi. sq.) than there are
inside Forest land boundaries (0.72 mi. sq.).
Following is a sample report.
+------------------------------------------------------------+
| COINCIDENCE TABULATION REPORT |
|------------------------------------------------------------|
|Location: spearfish Mapset: PERMANENT Date: Wed Jun 1 |
| |
| Layer 1: owner -- Ownership |
| Layer 2: roads -- Roads |
| Mask: none |
| |
| Units: square miles |
|------------------------------------------------------------|
| Window: North: 4928000.00 |
| West: 590000.00 East: 609000.00 |
| South: 4914000.00 |
+------------------------------------------------------------+
Panel #1 of 1
+--------------------------------------------------------+
| | owner | Panel Row Total |
| cat# | 1 | 2 | w cat 0 | w/o cat 0 |
|--------------------------------------------------------|
|r 0 | 50.63 | 37.49 | 88.12 | 88.12 |
|o 1 | 1.53 | 0.68 | 2.21 | 2.21 |
|a 2 | 2.92 | 0.72 | 3.64 | 3.64 |
|d 3 | 3.97 | 2.57 | 6.54 | 6.54 |
|s 4 | 0.65 | 1.36 | 2.00 | 2.00 |
| 5 | 0.19 | 0.00 | 0.19 | 0.19 |
|--------------------------------------------------------|
|Total | | | | |
|with 0 | 59.90 | 42.80 | 102.70 | 102.70 |
|--------------------------------------------------------|
|w/o 0 | 9.27 | 5.32 | 14.58 | 14.58 |
+--------------------------------------------------------+
+--------------------------------+
| | Table Row Total |
| cat# | w cat 0 | w/o cat 0 |
|--------------------------------|
|r 0 | 88.12 | 88.12 |
|o 1 | 2.21 | 2.21 |
|a 2 | 3.64 | 3.64 |
|d 3 | 6.54 | 6.54 |
|s 4 | 2.00 | 2.00 |
| 5 | 0.19 | 0.19 |
|--------------------------------|
|Total | | |
|with 0 | 102.70 | 102.70 |
|--------------------------------|
|w/o 0 | 14.58 | 14.58 |
+--------------------------------+
r.coin calculates the coincidence of two raster map layers. Although r.coin allows the
user to rerun the report using different units, it is not possible to simply rerun the
report with different map layers. In order to choose new map layers, it is necessary to
rerun r.coin.
SEE ALSO
g.region, r.category, r.describe, r.reclass, r.report, r.stats
AUTHORS
Michael O'Shea,
Michael Shapiro,
U.S. Army Construction Engineering Research Laboratory
Last changed: $Date: 2008-05-16 12:09:06 -0700 (Fri, 16 May 2008) $
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