Image tilling

[Ryan Ollerenshaw]

What I am trying to do is to georeference aerial photos of a large area,
eventually the entire earth.  So what I need is to be able to specify the
lat/long of each photo (which I have) using only the lat/long coordinate
system.  I would like the user to be able to specify a bounding box (lat/long)
for a given area then have my mapserver return all the available images for
that given area.  Currently I think that I can use:

gdal_translate -a_ullr 180 0 210 -30  thm_dir_N-30_180.png thm_dir_N-30_180.tiff

To georeference all of my photos, then:

gdaltindex thm_dir.shp *.tif

To create a shape file with an index of all the photos, then I can specify my
layer in the mapfile as:

LAYER
  NAME "tileindex"
  STATUS ON
  TILEINDEX "thm_dir.shp"
  TILEITEM "Location"
  TYPE RASTER
END

But when I display this layer in MapServer I get a blank image,  and when I try
to view the shape file in ArcMap I can see my tiles but they are just displayed
as blank polygons with no images.  I think that my problem is incorrectly
specifying the EXTENT in the map file, but i am not sure what i should put if i
want my tiles to eventually cover then entire world.

Thanks,
-Ryan

Here is my entire map file incase that helps any:
NAME WMSDEMO
STATUS ON
SIZE 500 400
#EXTENT 0 0 2800 2800
#EXTENT -180 -90 180 90
EXTENT -9200000 -912631 3072800 3840000
#UNITS METERS
SHAPEPATH "../data"
IMAGECOLOR 255 255 255

WEB
  TEMPLATE test_template.html
  IMAGEPATH "/tmp/ms_tmp/"
  IMAGEURL "/ms_tmp/"
  METADATA
    WMS_TITLE   "WMS test mapserver"
    WMS_ACCESSCONSTRAINTS "none"
    #WMS_ONLINERESOURCE "http://neuron/cgi-bin/mapserv?map=display.map&"
    WMS_SRS     "EPSG:4326" #"AUTO:42003"
  END
END

PROJECTION
  "init=epsg:4326"
END

LAYER # Shaded Relief Raster
  NAME test_layer
  DATA bath_mapserver.tif
  STATUS ON
  TYPE RASTER
END

LAYER
  NAME "hpool"
  STATUS ON
  #DATA "thm_dir_00_030.tiff"
  TILEINDEX "thm_dir.shp"
  #TILEITEM "Location"
  TYPE RASTER
END


END # of map file