[R-sig-Geo] How to read multiple raster and serial correlation between series of rasters

[Malik Waseem Ali]

I have asked the below mentioned question a month before. Please guide me
if the question is not properly asked to the list member.
>
> Waseem Ali
>
>
> From: w1malik at gmail.com
> To: r-help at r-project.org
> Subject: FW: How to read multiple raster and serial correlation between
series of rasters
> Date: Thu, 2 Jun 2016 16:10:08 +0500
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> Dear members,
> With little effort in producing the code to read all nc files for Carbon
dioxide variables I have produced the following code:
> library(ncdf)ncfiles <- list.files("C:/site-download/AIRS/",
pattern='\\.nc$', full.names = TRUE)ncfilesncfname <-
ncfiles[1]ncfnamedname <-
"mole_fraction_of_carbon_dioxide_in_free_troposphere"ncin <-
open.ncdf(ncfname)print(ncin)lon <- get.var.ncdf(ncin, "Longitude")nlon <-
dim(lon)head(lon)lat <- get.var.ncdf(ncin, "Latitude")nlat <-
dim(lat)head(lat)print(c(nlon, nlat))co2array <- get.var.ncdf(ncin,
"mole_fraction_of_carbon_dioxide_in_free_troposphere")fillvalue <-
att.get.ncdf(ncin, "mole_fraction_of_carbon_dioxide_in_free_troposphere",
"Missval")fillvalueco2array[co2array == fillvalue] <-
NAlibrary(RColorBrewer)image(co2array, col = rev(brewer.pal(10,
"RdBu")))grid <- expand.grid(lon = lon, lat = lat)lonlat <-
expand.grid(lon, lat)lonlathead(lonlat)m <- 1co2.vec <-
as.vector(co2array)length(co2.vec)co2.df01 <- data.frame(cbind(lonlat,
co2.vec*1000000))names(co2.df01) <- c("lon", "lat", paste("co2",
as.character(m), sep = "_"))head(na.omit(co2.df01), 20)csvfile <-
"co20020901.csv"write.table(na.omit(co2.df01), csvfile, row.names = FALSE,
sep = ",")With the help of this code I can dump the values of Carbon
dioxide variables in latitude and longitude wise. sample of the csv file is
as under:      lon  lat    co2_126  -117.5 89.5 381.802050   -57.5 89.5
373.8030147 -175.0 88.0 382.7285148 -172.5 88.0 373.6800152 -162.5 88.0
371.6560153 -160.0 88.0 373.4450154 -157.5 88.0 374.3705I need help to tune
code to do this with iterative code for whole 120 raster to write it into
csv file. Column names should be like as 200301, 200302....up to 200312.
This starts from the January of 2003 till December of 2003 and so on for
the next year.   My next task to do the same for LST variable retrievable
from MODIS LST product of 0.05 degree resolution which is in hdf file
formate [I am trying to write the code to interpret the variable ]. I want
to resample it first to have on same spatial resolution as my first raster
then write to the another csv file in the same way before. After writing it
into the csv files I want to correlate the both variables and serial
correlation. Please guide to do it using R or any other way to deal with
the situations I have briefly explained. Also suggest for interpolation for
carbon dioxide variable first to make the raster layer. It may have missing
some values.
> Waseem Ali
>
> From: w1malik at hotmail.com
> To: r-help at r-project.org
> Subject: How to real multiple raster and serial correlation between
series of rasters
> Date: Sun, 29 May 2016 23:39:18 +0500
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> Hi,
> I have 120 raster (10 years) files
> in tif format of one variable (say X1) and same numbers for second
variables (Say
> X2). Each raster consists the mean monthly values of corresponding
variables. I
> want to write a script in R which operates the following operations:
>
> ·
> First reads the one by one
> raster from folder and save into the objects.
>
> ·
> Resample/aggregate the both
> raster over same spatial resolution 2˚ x 2.5˚.
>
> ·
> After resampling the all
> raster over same resolution, conversions of all raster to points by using
the
> rasterToPoint() function of raster library.
>
> ·
> After retrieving the same
> monthly raster values (like month of January for X1 and X2) into data
frame, I
> want to compute regression and correlation values for all 120 raster for
both
> variables (X1 and X2) and save into the data frame.
>
> Is there any way out to deal with
> such task.
>
>
> library(raster)
>
> x <- list.files("C:/site-download/",
> pattern = "*.tif", full.names = TRUE)
>
> x1 <- raster(x1)
>
> p <- as(x1, 'SpatialPixels')
>
> plot(x1)
>
> points(p)
> Resultant figure has been attached for you for only x1 variable. I have
also attached the X1 and X2 variable tif raster for January 2002 for
computation purpose. I need to operate it through loop for reading all
these rasters and computing the correlation of each pairs. My next step to
compute the Lag -1 correlations which is Serial Correlation for both
variables.
> Waseem Ali
>
>
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Ben Tupper
Bigelow Laboratory for Ocean Sciences
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