I have just started switching from Arc to R for some of my spatial analyses
and am stuck on a reclassification problem.  I am trying to use reclassify
from the package raster.  I have been able to run the examples, but cannot
run my own data.  I have tried to provide an example of my code using a
small subset of my data.  The reclassify does work for some values (about
9/10 of the grid cells), but not all.  In the example below, values 71,
145, and 231 are not reclassified.

The primary difference that I can find between my data and the worked
examples is that all examples seem to assume that a range of values from
continuous data are being reclassified, while my data are categorical
(numerical codes for land cover classes).  Instead of a range to single
value reclassification, I just want to reclassify each value to a single
different value (in some cases, some of the original data can be treated as
if they are a range, as shown in the example reclass matrix, but in reality
this is not the case).  I thought maybe I could just put the same value in
both the min and max columns, but that did not seem to work (value 71 in
the example).  But that is not the only problem, because 145 and 231 are
both values that I treated as if they were part of a range.  I do not get
any error
messages, just some values do not reclassify.

So I am out of ideas.  If I cannot use reclassify, is there another way to
classify ordinal or categorical raster data when I am not reclassifying a
range to single value? Thank you for any help!

> testarea

class       : RasterLayer
dimensions  : 34, 33, 1122  (nrow, ncol, ncell)
resolution  : 30, 30  (x, y)
extent      : 1200009, 1200999, 999992.1, 1001012  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96 +x_0=0
+y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
data source : in memory
names       : segap_scope
values      : 1, 231  (min, max)
attributes  :
        ID   COUNT
CLASS_NAMES       RED     GREEN      BLUE OPACITY
 from:   1 7128758                                  Open Water (Fresh)
0.3568627 0.4588235 0.6392157       1
 to  : 253  427139 Southern and Central Appalachian Oak Forest - Xeric
0.5372549 0.6666667 0.3294118       1

>
> #Open reclass table.  Three columns From/To Values for input range, new
value for output
> recls = read.csv(file="
SecondReclassTable_Rinput.csv", head=FALSE,
sep=",")
> recls = as.matrix(recls)
> recls

       V1  V2 V3
 [1,]   1   7  0
 [2,]  10  12  1
 [3,]  16  26  0
 [4,]  30  33  6
 [5,]  35  37  0
 [6,]  38  60  6
 [7,]  61  64  4
 [8,]  66  68  6
 [9,]  71  71  4
[10,]  72  74  3
[11,]  76  77  4
[12,]  79  79  3
[13,]  82  82  6
[14,]  85  85  4
[15,]  86  86  6
[16,]  90  96  4
[17,]  98  99  6
[18,] 100 100  4
[19,] 102 109  6
[20,] 118 118  0
[21,] 119 119  6
[22,] 124 127  0
[23,] 141 143  1
[24,] 145 149  0
[25,] 151 182  2
[26,] 183 188  4
[27,] 192 206  2
[28,] 207 207  0
[29,] 213 216  5
[30,] 217 217  1
[31,] 218 228  5
[32,] 231 233  4
[33,] 238 238  2
[34,] 245 250  5
[35,] 253 253  6


>
> ecos = reclassify(testarea, recls)
>
> ecos
class       : RasterLayer
dimensions  : 34, 33, 1122  (nrow, ncol, ncell)
resolution  : 30, 30  (x, y)
extent      : 1200009, 1200999, 999992.1, 1001012  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96 +x_0=0
+y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
data source : in memory
names       : layer
values      : 0, 231  (min, max)


-- 
--
C. Ashton Drew, PhD
NC Fish and Wildlife Coop. Research Unit
Dept. of Applied Ecology
North Carolina State University
cell: 919-886-2811
email: cadrew@ncsu.edu

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