Bathymetry .xyz data to raster

JoshuaCoates

I received some bathymetry data in .xyz format and am trying to figure out how to convert it to a DEM or raster of some sort. I need to generate some bathymetry profile graphs for a client. When I opened the text file to view the data, it is just one field with x,y,z data all together. The x,y data is in State Plane and the Z data is in NAVD88. The file is rather large (13.2mb) and when I tried to copy and paste the data into Excel to try and separate the data into separate fields, I received an error that not all of the data was copied (which I assume is because the file is too large?) Can anyone let me know how to convert this file into a raster?

RaphaelR

I recently had do something similar, convert rather large xyz files (up to 1.2GB) to rasters. Since the old script never really worked for me, i tried something with python/numpy. Making things a bit more complicated was the fact that in the xyz file records with no-data were simply omitted.

import numpy as np
import arcpy

# Inputs
xyzfile = "e:/file.xyz"
outname = "e:/raster.asc"
skiprows = 1
delimiter = ","

ncols = 5974
nrows = 5505
xllcorner = 682000
yllcorner = 205000
cellsize = 1.0
nodataval = -9999

zgrid = np.zeros((nrows,ncols), dtype=np.float32)
zgrid.fill(nodataval)

# process the xyz file
with open(xyzfile) as f:
        
        # if header found in xyz file, skip line 1
        if skiprows == 1: 
            next(f)
            
        # put all available xyz values into correct positions on the zeros grid, 
        # all other positions keep the nodatavalue    
        for line in f:
                
            item = line.rstrip().split(delimiter)
            #print item 
            idx = (float(item[0])-xllcorner) / cellsize
            idy = (float(item[1])-yllcorner) / cellsize
            
            zgrid[idy,idx] = item[2]

# write the header and grid to an ascii file
with open(outname, "w") as outfile:
            
        # write ascii raster header
        outfile.write("ncols " + str(int(ncols))+ "\n")
        outfile.write("nrows " + str(int(nrows))+ "\n")
        outfile.write("xllcorner " + str(xllcorner) + "\n")
        outfile.write("yllcorner " + str(yllcorner) + "\n")
        outfile.write("cellsize " + str(cellsize) + "\n")
        outfile.write("nodata " + str("%.2f" % float(nodataval)) + "\n" + "\n")
        
        # write grid to outfile
        np.savetxt(outfile,zgrid[::-1], fmt="%.2f", delimiter= " ")