I have trouble getting my data to create a grid using sp and gstat package in R. I have a relatively small data set with GPS coordinates and I want to interpolate my data and make a gridded map. My data is in a csv file and is currently not in a shapefile or raster.
I've so far been able to plot my data points with the "bubbles" function, and now I am trying to create a grid. But I constantly get this error:
gridded(test_2) = T suggested tolerance minimum: 0.75 Error in points2grid(points, tolerance, round) : dimension 1 : coordinate intervals are not constant
I am not sure why the intervals are not constant, or how it might be possible to "manipulate" them to be. I have measured distances from shore from 0-1000 m, that I normalized to 0-1.
Any suggestions on how to make the intervals constant?
Thanks !!
Karen
Code example:
library(sp)
library(gstat)
test_2_2 <- read.csv("test_2_2.csv")
summary(test_2_2)
Lat Long Sample.id Water.level Temp Salinity Chl_a
Min. :33.14 Min. :-117.4 Min. : 1.00 Bottom :34 Min. :19.00 Min. :30.43 Min. : 7.57
1st Qu.:33.14 1st Qu.:-117.3 1st Qu.: 69.25 Surface:36 1st Qu.:24.50 1st Qu.:33.40 1st Qu.: 22.63
Median :33.14 Median :-117.3 Median :102.50 Median :24.70 Median :33.45 Median : 29.07
Mean :33.14 Mean :-117.3 Mean : 95.54 Mean :24.46 Mean :33.34 Mean : 30.15
3rd Qu.:33.14 3rd Qu.:-117.3 3rd Qu.:129.75 3rd Qu.:25.10 3rd Qu.:33.47 3rd Qu.: 35.53
Max. :33.15 Max. :-117.3 Max. :153.00 Max. :25.95 Max. :33.94 Max. :116.07
NA's :1 NA's :5
Nitrate
Min. :0.1330
1st Qu.:0.4260
Median :0.5480
Mean :0.8324
3rd Qu.:0.7970
Max. :4.7700
NA's :11
coordinates(test_2_2) = ~Lat+Long
bubble(test_2_2, "Temp")
test_2 <- read.csv("test_2.csv") # Import grid data
names(test_2)
[1] "Dist" "Lat" "Long"
coordinates(test_2) = ~Lat+Long
class(test_2)
[1] "SpatialPointsDataFrame"
attr(,"package")
[1] "sp"
names(test_2)
[1] "Dist"
gridded(test_2) = T
suggested tolerance minimum: 0.75
Error in points2grid(points, tolerance, round) :
dimension 1 : coordinate intervals are not constant
