[mapserver-users] The Case of the Disappearing Roads

[thomas bonfort]

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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