[GRASS-user] Determining Datum From Projection Coordinates [SOLVED]

Rich Shepard rshepard at appl-ecosys.com
Thu Mar 3 15:48:45 EST 2011

On Thu, 3 Mar 2011, Tom Russo wrote:

> Well, maybe I'm wrong about that.  I used the "cs2cs" utility from the
> proj.4 system to convert the first line of your lat/lons to UTM in both
> NAD83 and NAD27, and in neither case did I get what is in the table for
> UTM:

   Interesting, Tom. Thanks for exploring as you did.

> So my guess based on two data points is that if you assume the more
> precise of your columns are the ones to take to the bank, and that the
> less precise was a correct rounding-off of a computation, that the UTMs
> are in NAD83. Of course, if the lat/lon columns are just *truncated*
> rather than rounded, all bets are off.

   Works for me.

> You'd have to do the same computation on more lines of the table to be
> sure, though.

   These data do not need to be so precise that I'll worry about it. I'll go
back and recreate the table using the UTM values rather than lon/lat values,
feed them through the awk script to remove missing values and the sed script
to format them correctly, and try again to import them into grass.

Much appreciated,


More information about the grass-user mailing list