The result is good, thanks a lot, but how can I with this method fill my raster
to color?
Le 17 mai 2011 à 15:43, Duncan Murdoch a écrit :
> I don't think filled.contour gives you access to the contour lines. If you
> use contourLines() to compute them, then you can draw them using code like
> this:
>
> contours <- contourLines(V2b,levels=paliers)
> for (i in seq_along(contours)) {
> x <- contours[[i]]$x
> y <- contours[[i]]$y
> lines( splines( seq_along(x), x)$y, splines( seq_along(y), y)$y )
> }
>
> but as I said, you won't get great results. A better way is to use a finer
> grid, e.g. by fitting a smooth surface to your set of points and using
> predictions from the model to interpolate.
>
> Duncan Murdoch
>
>
> On 17/05/2011 9:35 AM, Pierre Bruyer wrote:
>> I work with large datasets (10000 points) so I can't post them , but my
>> function is :
>>
>> create_map<- function(grd, level ,map_output, format = c("jpeg"), width_map
>> = 150, height_map = 150,...)
>> {
>>
>> ##sp<- spline(x = grd[,1], y = grd[,2])
>>
>> grd2<- matrix(grd[,3], nrow = sqrt(length(grd[,3])), ncol =
>> sqrt(length(grd[,3])), byrow = FALSE)
>>
>> V2b<- grd2
>>
>>
>> ##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
>> }
>>
>> ##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
>>
>> ##delete marge
>> par(mar=c(0,0,0,0))
>> filled.contour(V2b, col = colgraph, levels = paliers, asp = 1, axes =
>> FALSE, ann = FALSE)
>> dev.off()
>>
>> }
>>
>> where grd is a xyz data frame,
>> map_output is the path+name of the output image file,
>> and level is a matrix like this :
>>
>>
>> level<- matrix(0,10,4)
>> level[1,1]<- 1.0000E+00
>> level[2,1]<- 3.0000E+00
>> level[3,1]<- 5.0000E+00
>> level[4,1]<- 1.0000E+01
>> level[5,1]<- 1.5000E+01
>> level[6,1]<- 2.0000E+01
>> level[7,1]<- 3.0000E+01
>> level[8,1]<- 4.0000E+01
>> level[9,1]<- 5.0000E+01
>> level[10,1]<- 7.5000E+01
>>
>>
>> level[1,2]<- 102
>> level[2,2]<- 102
>> level[3,2]<- 102
>> level[4,2]<- 93
>> level[5,2]<- 204
>> level[6,2]<- 248
>> level[7,2]<- 241
>> level[8,2]<- 239
>> level[9,2]<- 224
>> level[10,2]<- 153
>>
>> level[1,3]<- 153
>> level[2,3]<- 204
>> level[3,3]<- 204
>> level[4,3]<- 241
>> level[5,3]<- 255
>> level[6,3]<- 243
>> level[7,3]<- 189
>> level[8,3]<- 126
>> level[9,3]<- 14
>> level[10,3]<- 0
>>
>> level[1,4]<- 153
>> level[2,4]<- 204
>> level[3,4]<- 153
>> level[4,4]<- 107
>> level[5,4]<- 102
>> level[6,4]<- 33
>> level[7,4]<- 59
>> level[8,4]<- 63
>> level[9,4]<- 14
>> level[10,4]<- 51
>>
>> Le 17 mai 2011 à 15:17, Duncan Murdoch a écrit :
>>
>>> On 17/05/2011 8:24 AM, Pierre Bruyer wrote:
>>>> Thank you for your answer, but the function spline() (and a lot of other
>>>> function in R) can't take in its parameters the original contour which
>>>> are define by a vector, i.e. :
>>>>
>>>
>>> If you post some reproducible code to generate the contours, someone will
>>> show you how to use splines to interpolate them.
>>>
>>> Duncan Murdoch
>>>
>>>> ##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)
>>>>
>>>>
>>>>
>>>> Le 17 mai 2011 à 13:05, Duncan Murdoch a écrit :
>>>>
>>>>> On 11-05-17 5:58 AM, Pierre Bruyer wrote:
>>>>>> I'm a French developer (so I am sorry if my english is not perfect). I
>>>>>> have a problem to smooth the contours of a map. I have a dataset with 3
>>>>>> columns, x, y and z, where x and y are the coordinates of my points and
>>>>>> z is evaluate to a qualitative elevation and his representation is a set
>>>>>> of colors, which is define by levels.
>>>>>>
>>>>>> The problem is the curve of my contour is so linear, and I would like a
>>>>>> more continuous contour. I use the function fitted.contour to draw my
>>>>>> map.
>>>>>
>>>>> If you use a finer grid of x,y values you'll get shorter segments and
>>>>> they will look smoother.
>>>>>
>>>>> You might be able to use a smooth interpolator (e.g. spline()) rather
>>>>> than linear interpolation, but those occasionally do strange things e.g.
>>>>>
>>>>> x<- c(1:4, 5.9, 6:10)
>>>>> y<- c(1:4, 7, 6:10)
>>>>> plot(spline(x,y, n=200), type="l")
>>>>> points(x,y)
>>>>>
>>>>> where one point is out of line with the others, but the curve
>>>>> overcompensates in order to stay smooth.
>>>>>
>>>>> Duncan Murdoch
>>>>
>>>
>>
>
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