[Tilecache] Some general Newb questions

[cmose]

First and foremost, I'm an utter GIS newb in general so a number of my
questions may be more general WMS related questions - I appreciate your
patience!

First, can someone clearly explain to me what exactly the boundbox setting
is and what should be selected for those values? Currently I have a map that
displays the whole world and can be zoomed in about 10 levels  - this pulls
from an internal Esri geoserver via WMS. I'm using OpenLayers for my client
side rendering.

I'm currently using the a maxExtent/bbox of 180,90,-180,-90. I've made
certain that the bbox matches the maxExtent. 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.

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.

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.

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. Will, once I hit zoom level 5 the number of tiles
it was trying to pull down was about 118,000, level 9 was a whopping 46
million (which, at the rate of 1.3 tiles/sec I was getting, would take a
somewhat unreasonably long time). Is this to be expected or have I mucked
something up somewhere along the lines?

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).
-- 
View this message in context: http://www.nabble.com/Some-general-Newb-questions-tf4947089.html#a14164085
Sent from the TileCache mailing list archive at Nabble.com.