<div dir="ltr"><div><div><div><br></div>Hi all,<br><br></div>I'm using mapserver to display a single VRT that brings together multiple linear TIF mosaics of historic aerial images. <br><br>LAYER<br>    NAME "Photos1967"<br>    DATA "Photos1967.vrt"<br>    STATUS ON<br>    METADATA<br>        "wms_title"         "ODOT 1967 Aerial Photos"<br>        "wms_group_title"     "historic_photos"<br>        IMAGEFORMAT         "PNG"<br>        "wms_srs"             "EPSG:3857"<br>    END<br>    PROJECTION<br>       "init=epsg:3857"<br>    END<br>    TYPE RASTER<br>    OFFSITE 255 255 255<br>END<br><br><br>I'm having trouble in that the settings I am using seem to cause the individual TIFs  to "cancel out" the overlap areas between the files, which contains gaps in a sequence that should look seamless.<br><br>See <a href="http://bit.ly/1N5iOZM">http://bit.ly/1N5iOZM</a> for an example of the blank spaces created between TIF files.<br><br></div>An example snippet of the VRT looks like this:<br><br><font size="1"><VRTDataset rasterXSize="137160" rasterYSize="940380"><br>  <GeoTransform> 2.2045589280046773e+005, 1.6409343787230763e+000, 0.0000000000000000e+000, 1.6572602506651357e+006, 0.0000000000000000e+000,-1.6409343787192308e+000</GeoTransform><br>  <VRTRasterBand dataType="Byte" band="1"><br>    <NoDataValue>2.55000000000000E+002</NoDataValue><br>    <HideNoDataValue>1</HideNoDataValue><br>    <ColorInterp>Gray</ColorInterp><br>    <SimpleSource><br>      <SourceFilename relativeToVRT="1">flightlines1967_1.tif</SourceFilename><br>      <SourceBand>1</SourceBand><br>      <SourceProperties RasterXSize="8142" RasterYSize="43231" DataType="Byte" BlockXSize="8142" BlockYSize="1" /><br>      <SrcRect xOff="0" yOff="0" xSize="8142" ySize="43231" /><br>      <DstRect xOff="124188" yOff="119485" xSize="8143" ySize="43234" /><br>    </SimpleSource><br>    <SimpleSource><br>      <SourceFilename relativeToVRT="1"></font><font size="1"><font size="1">flightlines1967</font>_2.tif</SourceFilename><br>      <SourceBand>1</SourceBand><br>      <SourceProperties RasterXSize="14367" RasterYSize="43419" DataType="Byte" BlockXSize="14367" BlockYSize="1" /><br>      <SrcRect xOff="0" yOff="0" xSize="14367" ySize="43419" /><br>      <DstRect xOff="115051" yOff="160932" xSize="14367" ySize="43418" /><br>    </SimpleSource><br></font><div><font size="1">  </VRTRasterBand><br></VRTDataset></font><br><br></div><div>Any suggestions as to how I can resolve the issue of the overlaps? <br><br>My Mapserver version is 6.2.1 (gdal 1.10)...<br><br></div><div>Tanya<br></div></div>