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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Travis,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Thank you for your ideas. The tiles themselves existed in Mapcache as white images so Mapcache returned a “valid” image instead of a 404. I was able to find
the white tiles by just deleting all the <1K files in the area. However, if I ever notice the issue again I will definitely consider using the mapcache_seed command line with a shapefile to force the tiles to rebuild... That would have been quicker than
searching for small files!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Thank You!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Sincerely,<o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Mark Volz, GISP</span></b><b><span style="font-family:"Calibri",sans-serif;color:#1F497D"><o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Lyon County GIS Coordinator<o:p></o:p></span></b></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Travis Kirstine <traviskirstine@gmail.com>
<br>
<b>Sent:</b> Wednesday, February 20, 2019 12:45 PM<br>
<b>To:</b> Mark Volz <MarkVolz@co.lyon.mn.us><br>
<b>Cc:</b> mapserver-users@lists.osgeo.org<br>
<b>Subject:</b> Re: [mapserver-users] Mapcache - best way to find broken or white tiles in a service?<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="background:pink"><b><span style="font-size:16.0pt;font-family:"Courier New";color:black">SWHHS/LYON/LINCOLN COUNTY SECURITY NOTICE:</span></b>
<o:p></o:p></p>
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<p class="MsoNormal" style="text-indent:12.0pt;background:pink"><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif">This email originated from an external sender. Exercise caution before clicking on any links or attachments and consider whether
you know the sender. For more information please contact IT support.<o:p></o:p></span></b></p>
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<p class="MsoNormal">You shouldn't have any cached "broken" tiles unless your source WMS is generating the white images (metatiles). I believe MapCache will generate a 404 and return a empty tile if configured. This may be the white tiles you are seeing. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"> <!-- errors<o:p></o:p></p>
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<p class="MsoNormal"> configure how error will be reported back to a client:<o:p></o:p></p>
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<p class="MsoNormal"> - log : no error is reported back, except an http error code.<o:p></o:p></p>
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<p class="MsoNormal"> - report : return the error message to the client in textual format<o:p></o:p></p>
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<p class="MsoNormal"> - empty_img : return an empty image to the client. the actual error code is in the X-Mapcache-Error http header<o:p></o:p></p>
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<p class="MsoNormal"> - report_img : return an image with the error text included inside. not implemented yet.<o:p></o:p></p>
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<p class="MsoNormal"> the default setting is to report the error message back to the user. In production, you might want to set this to "log"<o:p></o:p></p>
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<p class="MsoNormal"> if you're paranoid, or to "empty_img" if you want to play nice with non-conforming clients.<o:p></o:p></p>
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<p class="MsoNormal"> --><o:p></o:p></p>
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<p class="MsoNormal"> <errors>report</errors><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">It can be very difficult to locate and clean up tiles from a cache, the easiest method and in some cases the fastest is simply to create a new cache and delete the old one. One alternative is to use the mapcache_seed command line tool
to either -f force the creation of new tiles or use the -mode delete option to delete the tiles from the cache. BTW you can use a polygon (shapefile) with mapcache_seed to only update / delete the desired area using the -d flag. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Also if you are using a disk cache you might be using symlinks which will allow mapcache to "reuse" blank tiles. If this is the case you might need to find / delete the symlinks rather than a "file"<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><cache name="disk" type="disk"><o:p></o:p></p>
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<p class="MsoNormal"> <!-- base<o:p></o:p></p>
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<p class="MsoNormal"> Absolute filesystem path where the tile structure will be stored.<o:p></o:p></p>
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<p class="MsoNormal"> This directory needs to be readable and writable by the user running<o:p></o:p></p>
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<p class="MsoNormal"> Apache.<o:p></o:p></p>
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<p class="MsoNormal"> --><o:p></o:p></p>
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<p class="MsoNormal"> <base>/tmp</base><o:p></o:p></p>
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<p class="MsoNormal"> <!-- symlink_blank<o:p></o:p></p>
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<p class="MsoNormal"><b> Enable blank (i.e. uniform color) tile detection. Blank tiles will be</b><o:p></o:p></p>
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<p class="MsoNormal"><b> detected at creation time and linked to a single blank tile on disk</b><o:p></o:p></p>
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<p class="MsoNormal"><b> to preserve disk space.</b><o:p></o:p></p>
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<p class="MsoNormal"> --><o:p></o:p></p>
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<p class="MsoNormal"> <symlink_blank/><o:p></o:p></p>
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<p class="MsoNormal"></cache><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Tue, 19 Feb 2019 at 16:47, Mark Volz <<a href="mailto:MarkVolz@co.lyon.mn.us">MarkVolz@co.lyon.mn.us</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hello,<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">On my webmap I noticed a few broken (white) tiles in a single area from my mapcache server. I would like to know the best way to find broken tiles in my mapcache service.
<o:p></o:p></p>
<p class="gmail-m-3411408627808268408msolistparagraph"><span style="font-family:Symbol">·</span><span style="font-size:7.0pt">
</span>Initially I was concerned that I would need to the tile number and folder location by using the BBOX, WIDTH, and TILE RESOLUTION from the request. However, I figured out using the mapcache demo is easier to work with /mapcache/demo/<o:p></o:p></p>
<p class="gmail-m-3411408627808268408msolistparagraph"><span style="font-family:Symbol">·</span><span style="font-size:7.0pt">
</span>Would it be better just to delete any tile that is 1K or smaller? These problibly are tiles that are broken, or intended to be blank in the first place.
<o:p></o:p></p>
<p class="gmail-m-3411408627808268408msolistparagraph"><span style="font-family:Symbol">·</span><span style="font-size:7.0pt">
</span>What do others do to validate that the mapcache tiles have been built appropriately?<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Thanks!<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:#1F497D">Sincerely,</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span style="color:#1F497D">Mark Volz, GISP</span></b><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span style="color:#1F497D">Lyon County GIS Coordinator</span></b><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal">_______________________________________________<br>
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