[Tilecache] Some general Newb questions

cmose cjmose at gmail.com
Wed Dec 5 19:53:10 EST 2007


using mod_python
tilecache.cfg:
[mylayer]
type=WMSLayer
url=http://thisisanexample/mserver/wmsserver
extension=png
maxResolution=0.074645535421371464
extent_type=loose
bbox=-180,-90,180,90
srs=EPSG:4326
levels=10
layers=1,2,3

OpenLayers:
($('map') dimensions are w:810px, h:405px)

var mOpt = {
    minExtent:new OpenLayers.Bounds(-1,-1,1,1),
    maxExtent: new OpenLayers.Bounds(-180,-90,180,90),
    maxResolution:0.074645535421371464,
    numZoomLevels:10,
    buffer:1,
    controls:[],
    fallThrough:true
}

I create my layer with wrapDateLine:true (which I'm having a problem with
but I'll post a seperate email about that).

I resolved the issue with the overviewMap based on your helpful link (still
tweeking as at the lowest zoom leve, e.g., least detailed, the overviewMap
doesn't actually allow you to navigate anywhere. I suspect I need to specify
resolutions: in tilecache.cfg and include some additional resolutions).




Christopher Schmidt-4 wrote:
> 
> On Tue, Dec 04, 2007 at 06:37:57PM -0800, cmose wrote:
>> What I tend to get is, once I
>> load up my map, the initial tiles will show up in my map div (typically
>> about 6 tiles), but then there will be about 60 more image requests after
>> my
>> viewable tiles have already shown up. This happens pretty much every time
>> I
>> drag the map. Furthermore, rendering of cached tiles is still not
>> terribly
>> performant.
> 
> Using CGI or mod_python?
> 
>> Frequently a tile in the middle of the viewable area will not render
>> until
>> all the rest of those tile requests for, I presume, "unvisible" tiles
>> complete. I've tried playing with the OpenLayers buffer setting but this
>> does not appear to have much of an impact.
> 
> That seems unusual, and makes me wonder if perhaps you set it wrong. A
> webpage which demonstrates these problems would be most helpful: if not
> that, at least an HTML snippet showing your map and layer creation would
> be good.
> 
>> Also (I hate asking two questions in one post but don't want to clutter)
>> I
>> can't seem to get the OpenLayers overviewmap control to function at all;
>> I
>> get nothing but pink tiles in the overview control.
> 
> http://trac.openlayers.org/wiki/TroubleshootingTips
> 
> """
> If you have 'pink tiles':
> 
>     * Right click on the image, and get the image URL (via 'properties'
>     * in IE, or 'copy image URL' in other browsers)
>     * Paste the image URL into a browser. 
> """
> 
> http://openlayers.org/pipermail/users/2007-November/003953.html
> "So, the overview map control is trying to guess at the resolutions it 
> should use for its map.  And it's not guessing right in this case.  So 
> the solution is to be explicit.  Choose some resolutions that you know 
> TileCache will like:"
> 
>> And finally - just as a sanity check, I'm trying to use
>> tilecache_seed.py. I
>> set it up to seed my first layer of zoom, that worked fine and pulled
>> down
>> something like 800 tiles. 
> 
> Um, this sounds totally out of line with what I expect. That said, given
> the fact that you had 800 tiles in your first zoom, it doesn't surprise
> me at all that you got the numbers you did for the rest of the layers.
> (WEll, it sort of does, since the numbers don't entirely add up, but
> they're all within the right order of magnitude). 
> 
>> Thanks again - I know I haven't provided many concrete details about my
>> configuration; I'm currently at home and don't have that information
>> handy.
>> I believe I'm using TileCache 1.9 and OpenLayers 2.5 and running
>> TileCache
>> under mod_python on Apache 2.2 on a windows box (just remembered - I also
>> have extent_type=loose, if I'm recalling the wording of that parameter
>> correctly).
> 
> Your tilecache config section and your OpenLayers HTML will both help
> debug these issues further.
> 
> Regards,
> -- 
> Christopher Schmidt
> MetaCarta
> _______________________________________________
> Tilecache mailing list
> Tilecache at openlayers.org
> http://openlayers.org/mailman/listinfo/tilecache
> 
> 

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