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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