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    <div class="moz-cite-prefix">Hello Tomas<br>
      <br>
      as far as I can see the tiff are already in RGBA, from what I can
      see from the gdalinfo (see below)<br>
      <br>
      I tried using OFFSITE, but I couldnt see any difference in the
      output with or without it.<br>
      <br>
      In my opinion something is going wrong in the image treatments
      when a resampling is applied, as if the alpha transparency value
      for the border pixels was not <span id="result_box"
        class="short_text" lang="en"><span class="hps">preserved during
          the processing.<br>
          but then that's pure speculation.<br>
          <br>
        </span></span><br>
      Warning 1: TIFFReadDirectory:Unknown field with tag 37724 (0x935c)
      encountered<br>
      Driver: GTiff/GeoTIFF<br>
      Files: 592116.tif<br>
             592116.tfw<br>
      Size is 5020, 5020<br>
      Coordinate System is `'<br>
      Origin = (2591997.899999999906868,1117002.100000000093132)<br>
      Pixel Size = (0.200000000000000,-0.200000000000000)<br>
      Metadata:<br>
        TIFFTAG_SOFTWARE=Adobe Photoshop CS2 Windows<br>
        TIFFTAG_DATETIME=2013:04:18 14:52:47<br>
        TIFFTAG_XRESOLUTION=72<br>
        TIFFTAG_YRESOLUTION=72<br>
        TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)<br>
      Image Structure Metadata:<br>
        INTERLEAVE=PIXEL<br>
      Corner Coordinates:<br>
      Upper Left  ( 2591997.900, 1117002.100)<br>
      Lower Left  ( 2591997.900, 1115998.100)<br>
      Upper Right ( 2593001.900, 1117002.100)<br>
      Lower Right ( 2593001.900, 1115998.100)<br>
      Center      ( 2592499.900, 1116500.100)<br>
      Band 1 Block=5020x1 Type=Byte, ColorInterp=Red<br>
        Mask Flags: PER_DATASET ALPHA<br>
      Band 2 Block=5020x1 Type=Byte, ColorInterp=Green<br>
        Mask Flags: PER_DATASET ALPHA<br>
      Band 3 Block=5020x1 Type=Byte, ColorInterp=Blue<br>
        Mask Flags: PER_DATASET ALPHA<br>
      Band 4 Block=5020x1 Type=Byte, ColorInterp=Alpha<br>
      <br>
    </div>
    <blockquote
cite="mid:CAOM3y2hL44oLUiWVfBNy8jNiOFuMrRtKf7T1UL0o=KwG64Lj+w@mail.gmail.com"
      type="cite">
      <div dir="ltr">Hi Oliver,
        <div><br>
        </div>
        <div style="">Are you using mapserver's OFFSITE parameter,
          and/or do your tiff files have a nodata pixel set ?</div>
        <div style="">What happens if you convert your tiff to 32bit
          RGBA? (Not suggesting this is a valid workaround, just trying
          to narrow down the reasons for this).</div>
        <div style=""><br>
        </div>
        <div style="">--</div>
        <div style="">thomas</div>
      </div>
      <div class="gmail_extra"><br>
        <br>
        <div class="gmail_quote">On 18 April 2013 15:27, Oliver Christen
          <span dir="ltr"><<a moz-do-not-send="true"
              href="mailto:oliver.christen@camptocamp.com"
              target="_blank">oliver.christen@camptocamp.com</a>></span>
          wrote:<br>
          <blockquote class="gmail_quote" style="margin:0 0 0
            .8ex;border-left:1px #ccc solid;padding-left:1ex">dear all<br>
            <br>
            Im having some issue when applying PROCESSING
            "RESAMPLE=AVERAGE" or "RESAMPLE=BILINEAR" on some geotiff
            with transparency.<br>
            Either a clear or dark artifact appears on the border of the
            image, as seen on these examples:<br>
            <br>
            <a moz-do-not-send="true"
              href="http://dev.camptocamp.com/files/mapserver/fuzzy_edge_AVERAGE.png"
              target="_blank">http://dev.camptocamp.com/files/mapserver/fuzzy_edge_AVERAGE.png</a><br>
            <a moz-do-not-send="true"
              href="http://dev.camptocamp.com/files/mapserver/fuzzy_edge_BILINEAR.png"
              target="_blank">http://dev.camptocamp.com/files/mapserver/fuzzy_edge_BILINEAR.png</a><br>
            <br>
            if I specify no PROCESSING at all, the transparency is
            correct (but not the image "quality" which I wanted to
            improve with the PROCESSING ):<br>
            <a moz-do-not-send="true"
href="http://dev.camptocamp.com/files/mapserver/fuzzy_edge_NOPROCESSING.png"
              target="_blank">http://dev.camptocamp.com/files/mapserver/fuzzy_edge_NOPROCESSING.png</a><br>
            <br>
            at first I though the problem may have been caused by a
            fuzzy edge on the transparent edges in the geotiff:<br>
            <a moz-do-not-send="true"
              href="http://dev.camptocamp.com/files/mapserver/fuzzy_edge.png"
              target="_blank">http://dev.camptocamp.com/files/mapserver/fuzzy_edge.png</a><br>
            so I retreated one image to have clean edges:<br>
            <a moz-do-not-send="true"
              href="http://dev.camptocamp.com/files/mapserver/clean_edge.png"
              target="_blank">http://dev.camptocamp.com/files/mapserver/clean_edge.png</a><br>
            <br>
            but I couldnt see much difference in the result:<br>
            <a moz-do-not-send="true"
              href="http://dev.camptocamp.com/files/mapserver/clean_edge_AVERAGE.png"
              target="_blank">http://dev.camptocamp.com/files/mapserver/clean_edge_AVERAGE.png</a><br>
            <a moz-do-not-send="true"
              href="http://dev.camptocamp.com/files/mapserver/clean_edge_BILINEAR.png"
              target="_blank">http://dev.camptocamp.com/files/mapserver/clean_edge_BILINEAR.png</a><br>
            <br>
            there is no visible artifact for all border multipe of 90°
            (horizontal and vertical edges), only the non 90° edges show
            that problem.<br>
            <br>
            Im not knowledgeable with image manipulation and resampling
            with transaprency, so I dont know if this is normal or not.<br>
            <br>
            Any idea if there is some way to "solve" this "problem" ?<br>
            <br>
            thank you for your attention<br>
            <br>
            best regards<br>
            Oliver<br>
            <br>
            <br>
            <br>
            -- <br>
            Camptocamp SA<br>
            Oliver Christen<br>
            PSE A<br>
            CH-1015 Lausanne<br>
            <br>
            <a moz-do-not-send="true" href="http://www.camptocamp.com"
              target="_blank">www.camptocamp.com</a><br>
            <br>
            <a moz-do-not-send="true"
              href="tel:%2B41%2021%20619%2010%2023" value="+41216191023"
              target="_blank">+41 21 619 10 23</a> (direct)<br>
            <a moz-do-not-send="true"
              href="tel:%2B41%2021%20619%2010%2010" value="+41216191010"
              target="_blank">+41 21 619 10 10</a> (centrale)<br>
            <a moz-do-not-send="true"
              href="tel:%2B41%2021%20619%2010%2000" value="+41216191000"
              target="_blank">+41 21 619 10 00</a> (fax)<br>
            <br>
            _______________________________________________<br>
            mapserver-users mailing list<br>
            <a moz-do-not-send="true"
              href="mailto:mapserver-users@lists.osgeo.org"
              target="_blank">mapserver-users@lists.osgeo.org</a><br>
            <a moz-do-not-send="true"
              href="http://lists.osgeo.org/mailman/listinfo/mapserver-users"
              target="_blank">http://lists.osgeo.org/mailman/listinfo/mapserver-users</a><br>
          </blockquote>
        </div>
        <br>
      </div>
    </blockquote>
    <br>
    <br>
    <pre class="moz-signature" cols="72">-- 
Camptocamp SA
Oliver Christen
PSE A
CH-1015 Lausanne

<a class="moz-txt-link-abbreviated" href="http://www.camptocamp.com">www.camptocamp.com</a>

+41 21 619 10 23 (direct)
+41 21 619 10 10 (centrale)
+41 21 619 10 00 (fax)
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