[mapserver-users] Raster Upsampling

[Patrick Young]

Apologies, after revisiting this this morning, I can't reproduce what I was
seeing... now I do see the raster being bilinearly upsampled when I
overzoom.  Sorry about that!

On Fri, Sep 10, 2021 at 11:08 AM Patrick Young <
patrick.mckendree.young at gmail.com> wrote:

> As a quick follow up, a hack that worked to get around this was to make a
> VRT of the low resolution dataset wherein I set the resampling to bilinear
> in the VRT and set the resolution to much much higher, and that has the
> desired effect.  So the question is, is there a better way to achieve the
> same thing in mapserver.
>
> Thanks!
>
> On Fri, Sep 10, 2021 at 10:17 AM Patrick Young <
> patrick.mckendree.young at gmail.com> wrote:
>
>> Hello!
>>
>> I was curious if it is possible to have mapserver bilinearly upsample a
>> low resolution raster to a higher resolution when there is no reprojection
>> required.
>>
>> My setup is that I have a very low resolution image (a bathymetric layer)
>> and a much higher resolution image (aerial), both in web mercator.  When I
>> request a high resolution XYZ tile, the low resolution image remains
>> pixelated (it looks as if its is nearest neighbor upsampled) at the
>> raster's native resolution even though I have set in the PROCESSING
>> directive RESAMPLE=BILINEAR.
>>
>> I suspect from the docs that RESAMPLE only comes into play when we're
>> doing on-the-fly reprojection, is that correct?  When no reprojection is
>> required, but just simpler upsampling, can one change the kernel used?
>>
>> Many thanks!
>> Patrick
>>
>
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