I would like to use ocean depth as a covariate in a spatial model where I have a measured catch at a specific location, but depth at that site was not reported in the original dataset. The dataset 'scallop' in package SemiPar is a representative example:
> scallop[20:25,] latitude longitude tot.catch 20 39.46667 -72.66667 722 21 39.43333 -72.73333 41 22 39.40000 -72.80000 39 23 39.31667 -72.73333 0 24 39.33333 -72.85000 94 25 39.26667 -72.81667 7 I've been able to download a very large grid of depths in this area (33514 points) from: <http://topex.ucsd.edu/cgi-bin/get_data.cgi>. Given this data, I'm stuck at how to estimate the depth at each location in the scallops dataset. depths <- read.table("depths.txt", header=F,col.names=c("x","y","z")) depths$x <- depths$x - 360 ## subset the data keeping only negative depths depths <- subset(depths, depths$z < 0) ## Convert depths to a positive number depths$z <- (-1)*depths$z length(depths$z) Thanks. --Dale _______________________________________________ R-sig-Geo mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-geo
