[Gdal-dev] hatches rendering issues

[Frank Warmerdam]

Eric Lemoine wrote:
> Hello
> 
> (Resending this since it didn't make it due to too big attachments)

Eric,

The list is configure with a fairly restrictive limit on email size.
I'd suggest pointing to images on a web server you own or demonstrating
the issue with very small swatches.

> The result isn't satisfying as the horizontal hatches aren't equally
> spaced as they should be for the scales 1/20000 and 1/10000. It is a
> lot better for 1/5000, although some lines seem bolder than others.
> 
> (In my previous email, I attached some png images to illustrate the
> problem, but my email didn't make it to the list because of these
> attachments).
> 
> I've used several other combinations. For example, I tried to use "nearest"
> both with Gdal and MapServer. The results are very very bad.
> 
> Do you have suggestions?

It would be helpful to see the results, but generally it is hard to
downsample repeating patterns without odd aliasing effects.  The best
is to be very certain that exact factor of 2 downsamplings are done in
which case the algorithms should sample the data in a consistent way.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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