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Raster is a data format consisting of regular grids of values, usually stored in an image-like format.
0
votes
Accepted
histogram of raster coordinates in R
The histograms are different.
head(table(one))
##one
##31 32 33 34 35 36
## 1 2 1 2 2 2
head(table(two))
##two
##18 19 22 23 24 25
## 2 1 3 4 2 5
stem(one, 0.5)
# The decimal point …
5
votes
Accepted
Identifying value of closest non-NA pixel
You can do something along these lines:
Example data:
library(raster)
r <- raster(ncol=10,nrow=10, ext=extent(c(0,10,0,10)), crs='+proj=utm +zone=1')
r[] <- 1
r[15:42] <- 2
set.seed(0)
r[sample(ncell …
1
vote
Error during DEM interpolation for raster grid : data item in gstat object and newdata have ...
The general approach you are taking works for me with terra and with raster. … dem_rast <- raster(floor(extent(dem_points_clip)), res=5) …
3
votes
Detect whether there is a spatial polygon in a spatial extent
'sp' is a Spatial* object
library(raster)
e <- extent(c(0,10,0,10))
intersect(e, extent(sp))
But it may indeed be, as whuber points out, that the polygon is in fact not inside extent e. …
7
votes
Accepted
How do I get rid of edge effects while using focal in R to smooth a raster?
Also, as you want to fill in missing values, not change existing values, I would use NAonly = TRUE, together with pad=TRUE (to pad virtual rows and columns with NAs outside of the raster). … Here is an example:
library(raster)
# example data
logo <- raster(system.file("external/rlogo.grd", package="raster"))
set.seed(0)
i <- sample(ncell(logo), 200)
logo[i] <- NA
plot(logo)
m <- matrix …
3
votes
Random sampling of raster using R?
You can use the sampleRandom function:
library(raster)
r <- raster(ncol=30,nrow=20)
r[] <- 1:ncell(r)
x <- sampleRandom(r, ncell(r)*.3, asRaster=TRUE) …
1
vote
Multiply raster brick by vector based on codition from another vector in R
Here are three alternative approaches to terra::app that Jeffrey Evans proposed; instead using ifel, selectRange and lapp. I am not saying these are better in any way, but they may be easier to use.
J …
2
votes
How to store raster brick in memory, rather than on disk in R?
To load all values in RasterBrick into RAM you can use readAll
library(raster)
b <-brick("tmmn_2020.nc")
x <- readAll(b)
But this will not help you if you cannot have that much data in RAM, as you say …
1
vote
Accepted
Why Stacking rasters return all values as NAs?
The NA's here refer to the fact that the min and max value are unknown (this is no longer the case in the current version of 'raster'). …
1
vote
regression model with randomForest in raster package
Impossible to know from your description. But you can try things like the below to see what is going on:
# get values of a few cells
cells <- 100000:100010
x <- data.frame(w1[cells])
x
predict(s2.rf …
1
vote
Accepted
How to compute climatology of 3 days moving averages for rasters pixel by pixel?
x <- calc(st1, function(x) movingFun(x, 3, mean))
y <- st1 - x
4
votes
Accepted
Applying different equation based on conditional statement for raster value in R?
<- function(x,y) {
z <- rep(NA, length(x))
i <- which(y == 1)
z[i] <- x[i] * 3
i <- which(y == 2)
z[i] <- x[i] * 33
i <- which(y == 3)
z[i] <- x[i] * 333
z
}
library(raster … )
r1 <- r2 <- raster(nrow=5, ncol=5)
r1[] <- runif(ncell(r1)) * 10
r2[] <- round(runif(ncell(r2),1,3))
x <- overlay(r1, r2, fun=f) …
1
vote
Rasterize gives weird image
What you are seeing is a map of one raster cell (~ 9.5 - 10.5; 46.3 - 47.3) that has a single value (36). Had you provided more information, e.g. show(rMerge), it would have been very easy to spot. … Or use the raster(u, nrow=10, ncol=10)
u <- union(union(extent(ro),extent(ra)),extent(co))
rast <- raster(u, ncol=10, nrow=10)
r1 <- rasterize(ro, rast)
r2 <- rasterize(ra, rast)
r3 <- rasterize(co, rast …
1
vote
Include non-raster object in overlay function in R
whuber showed the way, but here's another way to get there (using the functions that match the operations he suggests)
d <- c(.25,.50,.75)
m <- cbind(1:3, d)
r3 <- reclassify(r2, m)
out <- r1 * r3
3
votes
Accepted
Extracting point data for each lat and long from raster file into a dataframe
If so, yo can do the following
# Your code (simplified)
library(raster)
files= list.files(pattern='\\.grd$', full.names=TRUE)
s <- stack(files)
pt<- read.csv("latandlong")
point <- SpatialPoints(pt)
df …