[R-sig-Geo] Warning messages "matrix(ratvalues, nrow = length(ratvalues)/length(ratnames))" when cropping rasters
Nelly Reduan
nell.redu at hotmail.fr
Tue Sep 19 22:55:37 CEST 2017
Hello,
Im working with one land cover raster and one shapefile representing study limit boundaries.
However, Im getting warning messages when I crop the raster using the function "crop" in
the package "raster".
> rast_crop <- crop(x=rast,y=(extent(limit_study_area_prj) + 1000)) # crop the raster to the extent of the study area
Warning messages:
1: In matrix(ratvalues, nrow = length(ratvalues)/length(ratnames)) :
data length [1923] is not a sub-multiple or multiple of the number of rows [147]
2: In .getRat(x, ratvalues, ratnames, rattypes) :
NAs introduced by coercion
3: In .getRat(x, ratvalues, ratnames, rattypes) :
NAs introduced by coercion
4: In .getRat(x, ratvalues, ratnames, rattypes) :
NAs introduced by coercion
This is the raster:
> rast
class : RasterLayer
dimensions : 65770, 53928, 3546844560 (nrow, ncol, ncell)
resolution : 30, 30 (x, y)
extent : -830370, 787470, 117960, 2091060 (xmin, xmax, ymin, ymax)
coord. ref. : +proj=lcc +lat_1=46 +lat_2=60 +lat_0=44 +lon_0=-68.5 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs +ellps=GRS80 +towgs84=0,0,0
data source : F:\rast.tif
names : rast
values : 10, 9999 (min, max)
This is the shapefile :
limit_study_area_prj
class : SpatialPolygonsDataFrame
features : 2
extent : -486868.6, -146688.1, 117964.1, 246335.5 (xmin, xmax, ymin, ymax)
coord. ref. : +proj=lcc +lat_1=46 +lat_2=60 +lat_0=44 +lon_0=-68.5 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs +ellps=GRS80 +towgs84=0,0,0
variables : 12
This is the extent of the shapefile
> extent(limit_study_area_prj)
class : Extent
xmin : -486868.6
xmax : -146688.1
ymin : 117964.1
ymax : 246335.5
Is there any way to avoid these warning messages? Are there consequences for extracting raster values (after cropping)?
Thank so much for your time
Have a nice day
Nell
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