<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Wed, Jul 10, 2013 at 3:08 PM, Mark Volz <span dir="ltr"><<a href="mailto:MarkVolz@co.lyon.mn.us" target="_blank">MarkVolz@co.lyon.mn.us</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hello,<br>
<br>
I converted a mr sid air photo to a tif file. The colors appear washed out and too bright compared to the mr sid file.<br>
<br>
<br>
I would like to create an image file that has the following three characteristics:<br>
<br>
1) Fast for Mapserver to read.<br>
2) Relatively the same size as the MrSID file. - I would prefer a file size that is no larger than twice the size of the Mr SID file, even if it means that I have to take a small hit by using compression<br>
3) retains the same image quality as the original MrSID file<br>
<br>
The following two commands made the image fast for mapserver, and relatively small. But the colors were washed out...<br>
<br>
c:\ms4w\apps\PipestoneMaps\Raster\Picto2013>gdal_translate -CO TILED=YES -CO PHOTOMETRIC=YCBCR -CO TFW=YES -CO COMPRESS=JPEG -CO BIGTIFF=YES MNPIPE13-SID-9INCH.sid New.tif<br>
c:\ms4w\apps\PipestoneMaps\Raster\Picto2013>gdaladdo -r average --config compress_overview JPEG --config photometric_overview YCBCR New.tif 2 4 8 16 32 64 128 256<br>
<br>
<br>
What can I do to improve the image quality, while retaining the speed and a moderate file size?<br>
<br>
Thanks<br>
<br>
Mark Volz, GISP<br>
GIS Specialist<br></blockquote><div><br><br></div><div>Mark,<br><br></div><div>Those are pretty much the commands that I regularly use to prepare imagery for mapserver. I have never experienced any noticeable color distortion. What does it look like with a straight <br>
gdal_translate MNPIPE13-SID-9INCH.sid New.tif<br></div><div>obviously that's not what you want for a final product, but it would be my first step toward 'debugging' the problem.<br><br>Rich<br></div><div> </div>
</div><br>-- <br>Richard Greenwood<br><a href="mailto:richard.greenwood@gmail.com">richard.greenwood@gmail.com</a><br><a href="http://www.greenwoodmap.com">www.greenwoodmap.com</a>
</div></div>