Dear Edzer,
I transformed my SpatialGridDataFrame into a SpatiaPointsDataFrame (by the
way is there any coercion method such as "as.SpatialPointsDataFrame"
available in sp instead of creating a new one for I have not found it ?).
But this does not change my problem: I need the vector of attributes to
follow through the change in the z position. Right now the order of the
values in the vector of attributes stays the same even if the z coordinates
change. Here is my code starting from the summary of the initial
SpatialGridDataFrame
> summary(tls.spgdf)
Object of class SpatialGridDataFrame
Coordinates:
min max
[1,] 828099 828139
[2,] 101834 101874
[3,] 322 374
Is projected: TRUE
proj4string :
[+init=epsg:27561 +proj=lcc +lat_1=49.50000000000001
+lat_0=49.50000000000001 +lon_0=0
+k_0=0.999877341 +x_0=600000 +y_0=200000 +a=6378249.2 +b=6356515
+towgs84=-168,-60,320,0,0,0,0 +pm=paris +units=m +no_defs]
Grid attributes:
cellcentre.offset cellsize cells.dim
1 828099.5 1 40
2 101834.5 1 40
3 322.5 1 52
Data attributes:
Min. 1st Qu. Median Mean 3rd Qu. Max.
0.000000 0.000000 0.000000 0.007572 0.000000 1.226000
# (i) 3D Matrix
(x.coord <- floor(coordinates(tls.spgdf)[,1]))
(y.coord <- floor(coordinates(tls.spgdf)[,2]))
(z.coord <- floor(coordinates(tls.spgdf)[,3]))
tls.xyz2 <- cbind(x.coord, y.coord, z.coord)
# (ii) SpatialPoints
tls.sp2 <- SpatialPoints(tls.xyz2, proj4string = CRS("+init=epsg:27561"))
# (iii) DataFrame (attribut z)
tls.df2 <- data.frame(d=tls.spgdf$d)
# (iv) SpatialPointsDataFrame
tls.spdf2 <- SpatialPointsDataFrame(tls.xyz2, tls.df2)
# Summary of DTM values
> summary(sge)
Object of class SpatialGridDataFrame
Coordinates:
min max
s1 828099 828139
s2 101834 101874
Is projected: TRUE
proj4string :
[+init=epsg:27561 +proj=lcc +lat_1=49.50000000000001
+lat_0=49.50000000000001 +lon_0=0
+k_0=0.999877341 +x_0=600000 +y_0=200000 +a=6378249.2 +b=6356515
+towgs84=-168,-60,320,0,0,0,0 +pm=paris +units=m +no_defs]
Grid attributes:
cellcentre.offset cellsize cells.dim
s1 828099.5 1 40
s2 101834.5 1 40
Data attributes:
Min. 1st Qu. Median Mean 3rd Qu. Max.
325.9 329.1 330.8 330.8 332.4 335.6
z.sge <- round(sge[[1]])
z <- coordinates(tls.spdf2)[,3]
tls.spdf2$z <- z
nz <- tls.spdf2[[2]] - z.sge[[1]]
tls.spdf2$nz <- nz
> summary(tls.spdf2)
Object of class SpatialPointsDataFrame
Coordinates:
min max
x.coord 828099 828138
y.coord 101834 101873
z.coord 322 373
Is projected: NA
proj4string : [NA]
Number of points: 83200
Data attributes:
d z nz
Min. :0.000000 Min. :322.0 Min. :-11.00
1st Qu.:0.000000 1st Qu.:334.8 1st Qu.: 1.75
Median :0.000000 Median :347.5 Median : 14.50
Mean :0.007572 Mean :347.5 Mean : 14.50
3rd Qu.:0.000000 3rd Qu.:360.2 3rd Qu.: 27.25
Max. :1.226040 Max. :373.0 Max. : 40.00
(x.coord2 <- coordinates(tls.spdf2)[,1])
(y.coord2 <- coordinates(tls.spdf2)[,2])
(z.coord2 <- tls.spdf2$nz)
tls.xyz3 <- cbind(x.coord2, y.coord2, z.coord2)
tls.sp3 <- SpatialPoints(tls.xyz3, proj4string = CRS("+init=epsg:27561"))
tls.df2 <- data.frame(d=tls.spdf2$d)
tls.spdf3 <- SpatialPointsDataFrame(tls.sp3, tls.df2)
--
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