I don't think the precision would affect anything... even
single-precision floats have more than enough range for typical terrain
applications. One might get some small loss of precision at large
magnitudes, but clipping or lopping shouldn't happen.
Can you send the file to me? I can then at least verify what is getting
exported and that the file doesn't contain clipped/lopped values.
Ray
Sorry, I located the plugin (it was in the wrong directory...) and have tried to export the file as a DSRB to import into Global Mapper. I've also tried the DSBB with the same results. I'm not sure if the problem is with the exporter, Global Mapper, the file format itself, or with my understanding of it. The files I have used are 10K, 5K, 1K square, all at 200m world scale point spacing. The calc button in the exporter dialog maps the elevation range as 1195.4041 to 10343.707 and the X,Y as one would expect..
I've managed to import the file into GM but I'm wondering if the elevation range is sufficient because the top third of mountain ranges is cut off- there are holes. Predictably, the larger the elevation range I specify in the export the more definition the terrain has in GM. The range produced by the calc button produces a file which GM cannot import or read. So I have tried other values, including negative values to increase the range- no luck. The maximum range that it will accept is 0 to 32000, which produces the lopping off effect. The help file for the plugin states that DSRB uses 64 bit doubles.
Would this be enough precision for the file and would a lack of precision explain the missing data ?
----- Original Message ----- From: "Ray Gardener" <rayg@xxxxxxxxxxxxxxxxxx> To: <leveller@xxxxxxxxxxxxx> Sent: Sunday, August 07, 2005 9:44 PM Subject: [leveller] Re: Leveller exports
The docs on the Surfer export plug-in seem straightforward. Is there some particular problem you're having?
Ray
Carl Lingard wrote:
I'm trying to get a dem file into Global Mapper. Could anyone tell me how to export from Leveller using the surfer v7 tagged binary option...?
