[mapserver-users] The Case of the Disappearing Roads

[Jeff McKenna]

For good karma (think of it as a way to thank Thomas and others for
tackling these questions) since you have a problem dataset handy, you
could create a tiny one or two features sample, with one layer, and
package all that in an archive with a README.txt and champion this
change through the tickets you mentioned.

Thanks!

-jeff


-- 
Jeff McKenna
MapServer Consulting and Training Services
http://www.gatewaygeomatics.com/


On 2013-08-12 4:14 PM, Joseph Marlin wrote:
> I am indeed using tile indices. I didn't think there would be any problem with that step, but just to be sure I went ahead and checked. They all looked ok, but I noticed that all the features that use tile indexes were the exact features that aren't showing up- small roadways, highway shields, etc. This was highly suspicious, and so I did a lot of digging. 
> 
> I recreated all the index shape files, this time using an old version of the tile4ms and shptree utilities that I had fortunately saved when I generated the map in 2011, and found that tileindex shapefiles were no much larger, and the map was rendered correctly! 
> 
> So, all I can say for sure is that the current version of tile4ms and shptree definitely did not work. This issue has been reported at least twice before it seems,
> http://trac.osgeo.org/mapserver/ticket/4259
> http://www.mail-archive.com/mapserver-users@lists.osgeo.org/msg17207.html
> 
> And I guess it is worth noting that this problem is still present in the latest version (MapServer version 6.2.1 OUTPUT=PNG OUTPUT=JPEG SUPPORTS=AGG SUPPORTS=FREETYPE SUPPORTS=ICONV INPUT=JPEG INPUT=SHAPEFILE).
> 
> Thanks so so much for your help! Let me know if you need further info.
> Joseph
> 
> 
> 
> ----- Original Message -----
> From: "thomas bonfort" <thomas.bonfort at gmail.com>
> To: "Joseph Marlin" <jmarlin at saucontech.com>
> Cc: "MapserverList OSGEO" <mapserver-users at lists.osgeo.org>
> Sent: Saturday, August 10, 2013 3:18:03 AM
> Subject: Re: [mapserver-users] The Case of the Disappearing Roads
> 
> Another thing to check: are you using a tileindex to reference your
> shapefiles, and if so, is the tileindex up-to-date (i.e. does it
> reference all your shapefiles).
> 
> --
> thomas
> 
> On 9 August 2013 20:04, Joseph Marlin <jmarlin at saucontech.com> wrote:
>> Thanks Thomas for the idea. I think I understand what you're asking. We pre-render all our tiles though, so while the screenshots are indeed showing a javascript viewer, that viewer is simply loading the prerendered images, retrieved from tilecache. And I have made sure that it isn't TileCache storing old tiles.
>>
>> ----- Original Message -----
>> From: "thomas bonfort" <thomas.bonfort at gmail.com>
>> To: "Joseph Marlin" <jmarlin at saucontech.com>
>> Cc: "MapserverList OSGEO" <mapserver-users at lists.osgeo.org>
>> Sent: Friday, August 9, 2013 1:54:41 PM
>> Subject: Re: [mapserver-users] The Case of the Disappearing Roads
>>
>> Joseph,
>> are the images you are posting a direct result of a getmap request
>> (i.e. with width=1007&height=454), or are they a screenshot of a
>> javascript client that is doing tiled requests to mapserver?
>> If those are tiled requests, are your layer/class minscale/maxscale
>> settings set to the exact values of your requested resolutions (i.e.
>> their might be some rounding errors in that case that make a
>> scale-dependant class appear or disappear based on floating point
>> rounding errors).
>>
>> --
>> thomas
>>
>> On 9 August 2013 19:03, Joseph Marlin <jmarlin at saucontech.com> wrote:
>>> The Case of the Disappearing Roads
>>>
>>> We create shapefiles with SQL querying world data that's been loaded into a PostgreSQL database. A python script requests tiles from mapserver at different zoom levels, and we generate the entire map like that.
>>>
>>> Now, at the sixth zoom level, level 3 roads (medium size roads) should be rendered. However, they are actually rendered only in a small section of the world, a box bounded by Toronto in the northwest, Cleveland in the southwest, and the Atlantic in the east. Elsewhere, level 3 roads are not rendered at all.
>>>
>>> As you can see in this image: http://i.imgur.com/6McvGOJ.png, the small gray roads, level 3 roads, (and highway shields, for that matter) that are visible on the top half suddenly stop being rendered by mapserver.
>>>
>>> In all the following more zoomed in levels, no roadways smaller than level 2 are rendered at all anywhere, as you can see here: http://i.imgur.com/8MTcPoi.png. I've verified that the shapefiles contain the data on the smaller roads as I have viewed them just fine with QGIS, as you can see here: http://i.imgur.com/S3W3Iy8.png
>>>
>>> I'm so confused as to what could possibly make roads disappear midway through a level. If it was a problem with my mapfile, why would they show up in part of Northeast US, but not anywhere else? Where do I even start looking to solve this?
>>>
>>> Thanks so much!
>>>
>>> Additional info:
>>> SRS: EPSG:900913
>>> Zoom levels: 19567.8792375, 9783.93961875, 4891.969809375, 2445.9849046875, 1222.99245234375, 611.496226171875, 305.7481130859375, 152.87405654296876, 76.43702827148438, 38.21851413574219, 19.109257067871095, 9.554628533935547, 4.777314266967774, 2.388657133483887,  1.1943285667419434, 0.5971642833709717, 0.29858214168548586
>>> Bounding box: -20037508.3427892,-20037508.3427892, 20037508.3427892,20037508.3427892
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