[GRASS5] remove error output from pj_do_proj()?

[William K]

case: location with orthographic projection, projecting from lat/long 
location that covers the whole globe.  The region is rectangular (of 
course) and the projection is a circle.  So there are many cells in the 
corners that don't map to points on the globe (almost 1/3 of the 
region).  But GRASS will try to project to them anyways (doesn't know 
until it tries), and give them null if there is an error (which is 
good).

For all of these cells, both at the allocating/reading stage and the 
projecting stage, it gives:

pj_transform() failed
cause: tolerance condition error

and moves on to the next cell.  There are many of these, and r.proj 
slows down as it writes all them to the terminal.  And during the 
projecting stage, to % progress is often scrolled off the top of the 
screen.


In the past (tho I never thought about it until now) I've had similar 
errors with other projections (don't remember which), I guess also 
where the inverse projection failed for a few cells.  And they also 
finished with no abnormalities in the projected data.


On Jul 27, 2004, at 5:29 PM, Paul Kelly wrote:

> On Tue, 27 Jul 2004, William K wrote:
>
>> Ocassionally when I project rasters, r.proj spews out a bunch of 
>> errors (pj_transform() failed...).  Most of the time they are 
>> harmless
>
> Could you give a few examples to make this clearer? AFAICT any time 
> I've seen an error it meant I was doing something wrong, or it was a 
> clue that the results were going to be erroneous etc.
>
> FWIW pj_do_proj used to only report that projection had failed---I 
> changed it to report the actual PROJ error string which I thought made 
> it much more helpful?
>
Yes, it could be useful.  But if I know that they are harmless (like 
the orthographic above), it would be nice to turn them off.  Or the 
other way - default to off, and turn them on if I notice problems.

-----
William Kyngesburye <kyngchaos at charter.net>
http://webpages.charter.net/kyngchaos/

"Mon Dieu! but they are all alike.  Cheating, murdering, lying, 
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weaklings.  And yet withal bound down by silly customs that make them 
slaves to their unhappy lot while firm in the belief that they be the 
lords of creation enjoying the only real pleasures of existence....

- the wisdom of Tarzan