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<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="765383513-16112009">Hi Jukka,</span></font></div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="765383513-16112009"></span></font> </div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="765383513-16112009">I'm not sure that I understand you correctly. I tried to clip 2m data coverage by 20cm data- get some holes in 2m data index file. And mapfile setup as
follow: </span></font></div>
<div dir="ltr" align="left"><font face="Arial" size="2"><span class="765383513-16112009"> 2m data shows between scale 200k to 100k</span></font></div>
<div dir="ltr" align="left"><font face="Arial" size="2"><span class="765383513-16112009"> 2m data with holes show between 100k to 500</span></font></div>
<div dir="ltr" align="left"><font face="Arial" size="2"><span class="765383513-16112009"> 20cm data shows between 100k to 500.</span></font></div>
<div dir="ltr" align="left"><font face="Arial" size="2"><span class="765383513-16112009"></span></font> </div>
<div dir="ltr" align="left"><font face="Arial" size="2"><span class="765383513-16112009">It doesn't help. I don't think mapserver can read polygons for tileindex. It sounds like using rectangle.</span></font></div>
<div dir="ltr" align="left"><font face="Arial" size="2"><span class="765383513-16112009"></span></font> </div>
<div dir="ltr" align="left"><font face="Arial" size="2"><span class="765383513-16112009">/Liang</span></font></div>
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<font face="Tahoma" size="2"><b>From:</b> Rahkonen Jukka [mailto:Jukka.Rahkonen@mmmtike.fi]
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<b>Sent:</b> den 16 november 2009 13:36<br>
<b>To:</b> Liang Jian; mapserver-users@lists.osgeo.org<br>
<b>Subject:</b> Re: [mapserver-users] performance problem with ortho images<br>
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<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009">Hi,</span></font></div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009"></span></font> </div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009">Is it necessary to show 2 m data at all in the areas where 20-50 cm imagery is available? If not you can first make tileindex shapefiles from 2 m images
and 20-50 cm images. Open both shapefiles with for example OpenJUMP and select and remove those polygons from 2 m shapefiles which are totally covered by you 20-50 cm tiles. Combine the two layer, save and use the result as a tileindex file for Mapserver.</span></font></div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009"></span></font> </div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009">There may be problems in the areas with overlapping images. To get the desired image to show on top it may be necessary to rewrite the shapefile by so that
it will be ordered so that the small pixel size images will be written last in the shapefile. Then they should be drawn on top of 2 m imagery.</span></font></div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009"></span></font> </div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009">If you want the show 2 m images for the whole area when zoomed far away, prepare still the combined shapefile with covered by -images removed. Then make
two scale dependent layers under the same group. Read 2 m data when scale is between 200k and 100k and switch then to the combined layer.</span></font></div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009"></span></font> </div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009">There may be better ways, this is the best I have invented this far for our own use.</span></font></div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009"></span></font> </div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009">Take care of creating enough many low-resolution layers with gdaladdo for far away zooms. Even then if Mapserver must open more than 20-40 image files
for filling the screen I would consider making a separate overview image by mosaicing the whole area together with something like 20-50-100 meter pixel size and using that image in the same image group.</span></font></div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009"></span></font> </div>
<div dir="ltr" align="left"><font face="Arial" color="#0000ff" size="2"><span class="793171012-16112009">-Jukka Rahkonen-</span></font></div>
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<font face="Tahoma" size="2"><b>Lähettäjä:</b> mapserver-users-bounces@lists.osgeo.org [mailto:mapserver-users-bounces@lists.osgeo.org]
<b>Puolesta </b>Liang Jian<br>
<b>Lähetetty:</b> 16. marraskuuta 2009 13:02<br>
<b>Vastaanottaja:</b> mapserver-users@lists.osgeo.org<br>
<b>Aihe:</b> [mapserver-users] performance problem with ortho images<br>
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<div><span class="996093710-16112009"><font face="Arial" size="2">Hi all,</font></span></div>
<div><span class="996093710-16112009"><font face="Arial" size="2"></font></span> </div>
<div><span class="996093710-16112009"><font face="Arial" size="2">I have a problem with mapserver handling ortho images. The situation is we have 2m data cover the whole country and 20-50cm data cover most cities. We setup mapfiles as 2m data shows between
scale 200k to 500 and 20-50cm data show between scale 100k to 500. Problem is when requirst data in the city ranges, mapserver first read data from 20-50cm dataset and then read from 2m dataset which is unnecessary as the 20-50cm data is enough and the best
solution is when there is no 20-50cm data, 2m data should be used instead. </font>
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<div><span class="996093710-16112009"><font face="Arial" size="2"></font></span> </div>
<div><span class="996093710-16112009"><font face="Arial" size="2">Do you have any idea how to avoid the unnecessary reading?
</font></span></div>
<div><span class="996093710-16112009"><font face="Arial" size="2"></font></span> </div>
<div><span class="996093710-16112009"><font face="Arial" size="2">Any suggestions will be welcome!</font></span></div>
<div><span class="996093710-16112009"><font face="Arial" size="2"></font></span> </div>
<div><span class="996093710-16112009"><font face="Arial" size="2">Thanks</font></span></div>
<div><span class="996093710-16112009"><font face="Arial" size="2"></font></span> </div>
<div><span class="996093710-16112009"><font face="Arial" size="2">/Liang</font></span></div>
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