[MapProxy] WMS service with a Tiles source

[Daniel Dye]

Hi,

I'm trying to configure my first MapProxy WMS service with a Tiles
source and I'm stuck.  The Openlayers Client isn't displaying tiles
east or south of Null Island (0N, 0W).  Here is the URI for that
client:
http://ec2-67-202-26-132.compute-1.amazonaws.com:8080/demo/?wms_layer=WeoGeo_MapView&format=image%2Fpng

At the minimum zoom, I see in the console output that these tiles are requested:
[2012-01-10 12:15:50,626] mapproxy.source.request - INFO - GET
http://mapview.weogeo.com/xyz/1/0/1.png 200 33.8 142
[2012-01-10 12:15:50,668] mapproxy.source.request - INFO - GET
http://mapview.weogeo.com/xyz/1/0/0.png 200 26.1 184

I would have expected /0/0/1.png and /0/0/0.png at that zoom level for
my EPSG:4326 tiles source.

The WMS service has similar symptoms: the returned image covers twice
the area that I'm expecting, which seems reasonable if z is
off-by-one.  Here is a screen-shot of that:
http://dandye-share.s3.amazonaws.com/WMS.PNG

So, is there some way to configure z to start counting from zero
rather than one?  Or, perhaps this a red herring and I'm just making a
silly mistake in my configuration?

Here is my complete config and thanks in advance for any help!
---
services:
 kml:
 demo:
 tms:
 wms:
   srs: ['EPSG:4326']
   image_formats: ['image/jpeg', 'image/png']
   md:
     title: MapProxy WMS Proxy
     abstract: This is the fantastic MapProxy.
     online_resource: http://mapproxy.org/
     contact:
       person: Your Name Here
       position: Technical Director
       organization:
       address: Fakestreet 123
       city: Somewhere
       postcode: 12345
       country: Germany
       phone: +49(0)000-000000-0
       fax: +49(0)000-000000-0
       email: info at omniscale.de
     access_constraints:
       This service is intended for private and evaluation use only.
       The data is licensed as Creative Commons Attribution-Share Alike 2.0
       (http://creativecommons.org/licenses/by-sa/2.0/)
     fees: 'None'

layers:
 - name: WeoGeo_MapView
   title: WeoGeo MapView
   sources: [my_cache]

caches:
 my_cache:
  sources: [my_source]
  grids: [my_grid]
  meta_buffer: 0
  meta_size: [1,1]
  disable_storage: true
  watermark:
    text: WeoGeo
    opacity: 255
    font_size: 44

sources:
 my_source:
   type: tile
   url: http://mapview.weogeo.com/xyz/%(z)s/%(y)s/%(x)s.png
   origin: nw
   grid: my_grid

grids:
 my_grid:
   base: GLOBAL_GEODETIC
   tile_size: [256, 256]
   bbox: [-180, -90, 180, 90]
   bbox_srs: 'EPSG:4326'

globals:
 cache:
   base_dir: './cache_data'
   lock_dir: './cache_data/locks'
 image:
   resampling_method: nearest
---

Regards,
Dan

--
____________________
Daniel Dye
WeoGeo, Inc.

Phone - (813) 235-4802
Web - www.weogeo.com
Linkedin - www.linkedin.com/in/dandye