Yes sure! I understand english very well but I am not very good when I wrote,
so I try to don't write too nonsense. I have post a precedent topic about that
but no one have find a response for the ensemble of the problem.
So, I would like to create a raster for a map in R. I have a dataset with
coordinates xy and for each points of a grid, and a z concentration in each
points. I would obtain the same result than the software "Surfer 9". I have two
constraints:
- a scale of colors for the rasters (and the colors).
- for aesthetic, the contours of each scale must be smooth
Now an exemple with imaginary data (My datasets have 10000 points):
x =
c(0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0)
y =
c(0,0,0,0,0,0,0,0,0,0,0,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.2,0.2,0.2,0.2,0.2,0.2,0.2,0.2,0.2,0.2,0.2,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.5,0.5,0.5,0.5,0.5,0.5,0.5,0.5,0.5,0.5,0.5,0.6,0.6,0.6,0.6,0.6,0.6,0.6,0.6,0.6,0.6,0.6,0.7,0.7,0.7,0.7,0.7,0.7,0.7,0.7,0.7,0.7,0.7,0.8,0.8,0.8,0.8,0.8,0.8,0.8,0.8,0.8,0.8,0.8,0.9,0.9,0.9,0.9,0.9,0.9,0.9,0.9,0.9,0.9,0.9,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0)
z =
c(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,10,5,6,0,0,0,0,0,0,0,0,0,3,6,9,15,14,12,0,0,0,0,0,0,0,0,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)
essai <- data.frame(x =x, y = y, z = z)
level3 <- matrix(0,6,4)
level3[1,1] <- 1
level3[2,1] <- 5
level3[3,1] <- 10
level3[4,1] <- 15
level3[5,1] <- 25
level3[6,1] <- 30
level3[1,2] <- 0
level3[2,2] <- 0
level3[3,2] <- 0
level3[4,2] <- 0
level3[5,2] <- 255
level3[6,2] <- 255
level3[1,3] <- 0
level3[2,3] <- 0
level3[3,3] <- 255
level3[4,3] <- 255
level3[5,3] <- 0
level3[6,3] <- 0
level3[1,4] <- 0
level3[2,4] <- 255
level3[3,4] <- 0
level3[4,4] <- 255
level3[5,4] <- 0
level3[6,4] <- 255
## grd is the xyz dataframe, level is the matrix level3,and map_output is the
path where
##you want save the image.
create_map <- function(grd, level ,map_output, format = c("jpeg"), width_map =
150, height_map = 150,...)
{
grd2 <- matrix(grd[,3], nrow = sqrt(length(grd[,3])), ncol =
sqrt(length(grd[,3])), byrow = FALSE)
##creation of breaks for colors
i<-1
paliers <- c(-1.0E300)
while(i<=length(level[,1]))
{
paliers <- c(paliers,level[i,1])
i <- i+1
}
paliers <- c(paliers, 1.0E300)
##scale color creation
i <- 1
colgraph <- c(rgb(255,255,255, maxColorValue = 255))
while(i<=length(level[,2]))
{
colgraph <- c(colgraph, rgb(level[i,2],level[i,3],level[i,4],
maxColorValue = 255))
i <- i +1
}
### now many possibilities, this is the possibility with get contour of map
grd2 <- rbind(-1E100, grd2, -1E100)
grd2 <- cbind(-1E100, grd2, -1E100)
x <- seq(from=min(grd[,1]), to=max(grd[,1]), length =
sqrt(length(grd[,1])))
y <- seq(from=min(grd[,2]), to=max(grd[,2]), length =
sqrt(length(grd[,2])))
x <- c(min(grd[,1])-0.01, x , max(grd[,1])+0.01)
y <- c(min(grd[,2])-0.01, y , max(grd[,2])+0.01)
contours <- contourLines(x, y,grd2,levels=paliers)
##user can choose the output format (default is jpeg)
switch(format,
png = png(map_output, width = width_map, height = height_map) ,
jpeg = jpeg(map_output, width = width_map, height = height_map,
quality = 100),
bmp = bmp(map_output, width = width_map, height = height_map),
tiff = tiff(map_output, width = width_map, height = height_map),
jpeg(map_output, width = width_map, height = height_map))
## drawing map
par(mar=c(0,0,0,0),xaxs="i", yaxs="i")
plot(0,col="white",main="polygon()", asp = 1, axes = FALSE, ann =
FALSE,xlim=c(min(grd[,1 ]),max(grd[,1])), ylim =
c(min(grd[,2]),max(grd[,2])),type = "n")
for (i in seq_along(contours)) {
x <- contours[[i]]$x
y <- contours[[i]]$y
c <- contours[[i]]$level
j <- 1
tmp <- 0
while(j < length(level[,1])+1 && tmp == 0){
if( c == paliers[j]){
tmp <- j
}
j <- j+1
}
a <- spline( seq_along(x), x)$y
b <- spline( seq_along(y), y)$y
polygon( a, b ,col = colgraph[tmp], border = NA)
}
dev.off()
}
Here I use the solution of Duncan Murdoch, it is almost that I want, now I try
to resolve the default of his methods, e.g. I don't want smooth the contour (
the border) of my raster.
Thank for your help :-))
(Sorry for the spam, I have forgotten to send the mail to r-help)
Le 24 mai 2011 à 12:23, David Winsemius a écrit :
>
> On May 24, 2011, at 5:40 AM, Pierre Bruyer wrote:
>
>> I have seen this package and especially the 'perimeter' function, and it has
>> not a 'levels' parameters like a lot of other functions, and this is a big
>> problem for my project.
>
> Without a reproducible example it is difficult to know what you expect from a
> `levels` parameter, but I can get particular contour levels to be drawn for
> crossed-cubic regression splines. It would be more productive if you offered
> a minimal example to be worked on.
>
> --
> David.
>> Otherwise I find this package have a better architecture than the other
>> spatial package ^^
>>
>>
>> Le 24 mai 2011 à 10:52, David Winsemius a écrit :
>>
>>>
>>> On May 23, 2011, at 5:55 AM, Pierre Bruyer wrote:
>>>
>>>> Hello everybody,
>>>>
>>>> I search a function which returns the contour of map with levels like
>>>> contourLines, but I would like this function return the border of the map
>>>> too, because the function contourLines cannot consider the corner of the
>>>> map and it is not adapted to fill polygon after that.
>>>
>>> Frank Harrell has a `perimeter` function in his `rms` package which he uses
>>> to establish (and optionally draw) boundaries around 2D regions with
>>> sufficient data to yield meaningful estimates. The plotting is handed off
>>> to lattice functions. His default plotting function for 2D plotting is
>>> contourplot. It didn't take that long to make the transition to rms+lattice
>>> and I have been very pleased with the integration of the two.
>>>
>>> There is also a chull (convex hull) function although at the moment I do
>>> not remember which package it resides in.
>>>
>>>
>>>>
>>>> Thanks in advance
>>>>
>>>> Pierre Bruyer
>>>> ______________________________________________
>>>> R-help@r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide
>>>> http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>> David Winsemius, MD
>>> West Hartford, CT
>>>
>>
>
> David Winsemius, MD
> West Hartford, CT
>
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