Dear John,
A real life example is available at https://doi.org/10.5281/zenodo.2784012.
The idea is that the database returns a randomised set of points. You need
to overlay these points with your sampling framework. The final sample is
the set of points with the lowest ranking. The grtsdb package
Dear Thierry,
Thank you so much for your reply. Yes, the loss of the spatial balance once
the two-tiered approach is not accounted for was what was worrying me.
The incorporation of region as a random effect has two issues - 1) the
overall sampling area is a lake, and "regions" don't make sense i
Dear John,
Your procedure will create a spatially balanced level 1 sample (10
"regions") and within those regions a spatially balanced level 2 sample.
When you ignore the structure, there is no longer a spatial balance. So
you'll need to incorporate the two level sampling structure in your
analysi
On Thu, 7 Oct 2021, John Wilson wrote:
Oh, sorry - I normally use the grts() function from the spsurvey package.
My hacky approach was to make 10 balanced points with grts(), followed by
imposing a 5 km buffer around each one, and either systematic sampling
within the buffer circle, or running a
Oh, sorry - I normally use the grts() function from the spsurvey package.
My hacky approach was to make 10 balanced points with grts(), followed by
imposing a 5 km buffer around each one, and either systematic sampling
within the buffer circle, or running a separate GRTS for the 5 points
within eac
On Thu, 7 Oct 2021, John Wilson wrote:
Hi everyone,
I'm working on a sampling design using GRTS, but I'm running into a
logistics problem. The field crew can set 5 nets per day, but only within a
5 km stretch, due to travel time constraints. With 10 sampling days, that's
a total of 50 sites. Th
Hi everyone,
I'm working on a sampling design using GRTS, but I'm running into a
logistics problem. The field crew can set 5 nets per day, but only within a
5 km stretch, due to travel time constraints. With 10 sampling days, that's
a total of 50 sites. The overall sampling area is huge, so runnin
Dear all,
I would like to know if anybody knows how to convert my tiff (or jpg)
file to "rst" raster format in R.
I need to convert my image extension from *.tif to *.rst so that I can open
it in IDRISI software for applying BELClassification (soft classification,
or Dempster shafer Theory)
--
Dear all,
I have put the code that I've posted before into a package. The package is
available on R-forge.
install.packages("GRTS", repos="http://R-Forge.R-project.org";)
Any comments are welcome.
Best regards,
Thierry
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research In
Tukey
-Oorspronkelijk bericht-
Van: r-sig-geo-boun...@r-project.org [mailto:r-sig-geo-boun...@r-project.org]
Namens Dick Brus
Verzonden: maandag 11 februari 2013 15:45
Aan: r-sig-geo@r-project.org
Onderwerp: [R-sig-Geo] GRTS sampling
I try to understand the hierarchical randomization as appli
Dick--
I can't explain exactly why, but having your design draw all 16 points is a
problem, even though one might expect that do.sample=FALSE would ignore the
panel size.
frame<-expand.grid(x=seq(from=1,to=4,by=1),y=seq(from=1,to=4,by=1))
design.2 <- list(None=list(panel=c(P1=4),seltype="Equal"))
I try to understand the hierarchical randomization as applied in the GRTS
design.
I randomized 16 points on a square grid, see R script below. The argument
do.sample was set to FALSE, so that the result consists of a dataframe of
all 16 points instead of a GRTS sample. When plotting the order o
ens Dick Brus
Verzonden: maandag 11 februari 2013 9:51
Aan: r-sig-geo@r-project.org
Onderwerp: [R-sig-Geo] GRTS-sampling
I try to understand the hierarchical randomization as applied in the GRTS
design.
I randomized 16 points on a square grid, see R script below. The argument
do.sample was set
I try to understand the hierarchical randomization as applied in the GRTS
design.
I randomized 16 points on a square grid, see R script below. The argument
do.sample was set to FALSE, so that the result consists of a dataframe of
all 16 points instead of a GRTS sample. When plotting the order of
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