Raster scaling near edges #1844

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ramunasd opened this Issue May 15, 2013 · 3 comments

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@ramunasd
Contributor

issue

Here is same place rendered at same zoom. In left rendering is performed using renderd, in right - using nik2img.py. As you can see there is visible intersection between metatiles due to improper raster scaling around edges. All scaling methods shows +/- same issue.

Layer style:

<Style name="hillshade_raster">
    <Rule>
        <RasterSymbolizer scaling="lanczos"/>
    </Rule>
</Style>
<Layer name="hillshade">
    <StyleName>hillshade_raster</StyleName>
    <Datasource>
      <Parameter name="type">gdal</Parameter>
      <Parameter name="file">hillshade.vrt</Parameter>
    </Datasource>
</Layer>

Live example:
http://openmap.lt/#l=55.27888,20.98393,17,L

@artemp
Member
artemp commented May 15, 2013

@ramunasd - yes, this is a known issue. I'll have a look what we can do maybe mirroring pixels at edges might improve visual output.

@four43
four43 commented Jul 22, 2015

+1 We are having a similar issue when using tiled raster images, the tiles have 1px borders at some zoom levels where the Map background-color is applied.

@tds4u
tds4u commented Feb 21, 2017

Could this be the same problem for adding raster files AND background color?

#3623

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