Have you think about whether if the result of the extract function in the
raster library compare to the result from other GIS software?
I found some weird result when I compared it to the result from Zonal
Statistic from arcGIS and qGIS.
I was wondering there were some wrong with the raster::extrac
I also found issues with the raster::extract function, for some reason, I
got crazy values when I compared the resulting value with the one from
QGIS(Zonal Statistics Plugin) and ArcGIS（zonal statistics), while the value
from qgis and arcgis were close but the raster::extract has a lot of
disturban
I used this code before and it works, see the link:
http://hydrology.usu.edu/taudem/taudem5/TauDEMRScript.txt
Also you may check this link (
http://gis.stackexchange.com/questions/84694/flow-accumulation-in-r) in
stackexchange.
Hope it helps.
Peter
On Wed, Nov 18, 2015 at 9:35 AM, André Bertonc
Hi Tim,
I installed the packages with the hints (with devtools and leaflet library)
successfully, however, when I tried to run the code from
http://environmentalinformatics-marburg.github.io/web-presentations/20150723_mapView.html
I got issues:
First, the error came for
meuse_rst <- stack(meuse.g
Hi Nahm Lee and R-sig-geo,
I am quite interested in the IDW interpolation comparing to other methods
such as Krige, I have a code like this which I think also did the IDW:
library(gstat)
library(maptools)
library(raster)
dat71 <- readShapePoints("d:/FireDanger/IDW/71stations.shp")
bubble(dat71,"V
ond for 10 files, almost 15 second/per
file. This is significant!
I appreciated your patience and effort for make R really powerful. Thanks
to you all for the help.
Cheers,
Ping
On Thu, Apr 10, 2014 at 5:20 PM, Jonathan Greenberg wrote:
> Responses below:
>
> On Thu, Apr 10
UM_THREADS=ALL_CPUS to parallelize the operation -- in
> gdalUtils, this would be:
>
> gdalwarp(...,multi=TRUE,wo="NUM_THREADS=ALL_CPUS")
>
> # See: http://lists.osgeo.org/pipermail/gdal-dev/2012-June/033084.html
>
> If you are trying to warp a LOT of images, you can also u
its default settings (1e+08 cells on my machine -- about 750mb
> of RAM usage if each cell is 64 bits), and 2) adjust the chunk size to
> maybe 250mb (3e+07 cells) If you leave your settings like that,
> particularly on Windows, you'll end up with out-of-memory crashes
> fairly
gt; --j
>
> On Mon, Apr 7, 2014 at 3:30 PM, Alex Zvoleff
> wrote:
> > On Mon, Apr 7, 2014 at 4:05 PM, ping yang
> wrote:
> >
> >> Dear r-sig-geo,
> >>
> >> I plan to reproject from lonlat to UTM for a bunch of 10 meter NED files
> >>
Dear r-sig-geo,
I plan to reproject from lonlat to UTM for a bunch of 10 meter NED files
(large) using a R script(I did it successfully for the 30 meter DEM), I
used the following code to run:
rasterOptions(chunksize = 1e+10, maxmemory = 1e+12) #need to allow bigger
chunksize for the processing!!
Hi r-sig-geo,
previously I used following code to extract time series value for a given
coodinate from a netcdf file:
require(raster)
require(ncdf)
require(sp)
X1 <- -90.5167
Y1 <- 33.45
MS <- cbind(X1,Y1)
p <- SpatialPoints(MS)
year <- 1981
setwd("e:/PRISM/NetCDF/")
filename <
to a rasterbrick
> > object.
> > c) Use the over function and do an overlay between the points and the
> > rasterbrick. You will get a SpaitalPointsDataFrame object, with the
> > data associated to each point.
> > d) Save the data into a single file.
> >
> > This shou
Hi,
The purpose is to generate weather information(tmin,tmim,prcp) for every 4
KM (every 4KM there is a point represent that grid) for 32 years throughout
Contingent U.S.
I want to run several states simultaneously which I want it run them
parallel.
Thanks,
Ping
On Sun, Feb 2, 2014 at 1:45 PM,
Hi r-sig-geo,
I am using the following script to extraction weather information for each
point (from a rasterized shapefile for the COUS) which generate about
460,000 files:
Originally I read the coordinates from a shapefile:
Library(rgdal)
pl <- readOGR(".","US_2_points")
then I used the
na, IL 61801
> > Phone: 217-300-1924
> > http://www.geog.illinois.edu/~jgrn/
> > AIM: jgrn307, MSN: jgrn...@hotmail.com, Gchat: jgrn307, Skype: jgrn3007
> >
> > [[alternative HTML version deleted]]
> >
> > ___
> > R-sig-G
uot;),varname='tavg')
a <-raster(paste("prcp.3MIN.1981-2010_yearmean_NE.nc
",set=""),varname='prcp')
a <- as.matrix(a)
b <- as.matrix(b)
emd2d(a, b)
This function runs forever to finish (and it used up the memory).
Thanks,
Ping
--
Ping Yang, Ph.
...@krugs.de (Rainer M. Krug) wrote:
> Ivailo writes:
>
>> On Mon, May 13, 2013 at 8:13 PM, ping yang wrote:
>>> Dear Ivailo,
>>>
>>> Is this method can be used to quantify the spatial variability of two
>>> raster grids? Or Is there other measurement
Dear Ivailo,
Is this method can be used to quantify the spatial variability of two
raster grids? Or Is there other measurement will be better to do this?
Previously I posted a topic on how to compare two grids regarding to see
the difference on spatial variabilities(e.g. two temperature grids). I
Dear r-sig-geo,
I have gridded surface data for precipitation, temperature in the format of
netcdf for different sources(different downscaling methods), and I want to
know which one preserve the spatial variability of original data(at a
coarser resolution) best.
Is there a function or method can
generate a file and then use ncdf funcitons to read and then plot.
Thanks,
Ping
--
Ping Yang, Ph.D.
CUNY Environmental Crossroads Initiative
The City College of New York - CUNY
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R
Hi R users,
I saw a plot like this:
[image: Inline image 1]
I am wondering how to generate this plot (especially plotting the three
items for each season), Can anyone here give me some hints/instructions on
this plot?
Thanks and Regards,
--
Ping Yang, Ph.D.
CUNY Environmental Crossroads
Dear R,
I have a question for conducting a spatio-temporal inquiry, suppose I have
a time series of air temperature data for 100 years for my domain, can I
perform a inquiry like this " *How many days are there temperature above 40
degree *(CC) and get all these days", I noticed there are evolving
Hi,
The spatio-temporal tasks are spectacular! Can they bundled in a library or
in one package?
Actually, if the tasks can be imported into ncdf or Rnetcdf (which is
natively a space-time data), that will be extremely useful.
Thanks,
Ping
On Mon, Jan 28, 2013 at 2:45 PM, Edzer Pebesma <
edzer
Hi,
Is this zonal function works on NetCDF file?
Ping
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over
all the spatial area like gridboxmean, monmean in cdo)
2) do some zonal statistics (like in the GIS Zonal statistics) together
with a shape file or mask.
Looking forward to your suggestions.
Best Regards
Ping
--
Ping Yang, Ph.D.
CUNY Environmental Crossroads Initiative
Marshak Science Building
ing for your input data (in the next version of raster, it is
> attempted to automate that).
>
> Robert
>
> On Thu, Oct 18, 2012 at 7:47 PM, ping yang wrote:
>
>> Hi R user,
>>
>> I want to do a transform (re-projection) from a Lambert Conformal Conic
>>
gt; than willing to reuse :-) but am wondering where to look.
>
> Your coding recommendations are appreciated, as would be pointers to
> helpful resources. Thanks in advance, and feel free to forward,
> Tom Roche
>
> ___
> R-sig-Geo
Hi,
I am a newbie of R, I have time series (6 hours) weather data(represented
as muti-layer grids), what I plan to do is to aggregate these grids
temporally(from 6 hours to daily), Can I do it with R? some instructions or
suggestions?
Thanks,
Ping
--
Ping Yang, Ph.D.
Postdoctoral
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