[Tilecache] TileCache + MapServer + Openalyers + WMS (Google Mercator)

[Òscar Vidal Calbet]

Hi everyone!

I'm using TileCache + MapServer + OpenLayers and trying to publish a
WMS from Geotiff in Mercator (EPSG:900913).  I'm having difficulties
and the result is not that I expect. Below are the different parts of
my problems.


Bathymetry.tif
================================
Geotiff file in  EPSG:900913
Corner Coordinates:
Upper Left  (-5038852, 5970000)
Lower Left  (-5038852, 3420000)
Upper Right (-1412452, 5970000)
Lower Right (-1412452, 3420000)


WMS.map
================================
MAP
	NAME "WMS-test"
	STATUS ON
	SIZE 600 400

	# its The same extend that the file Bathymetry.tif in projected
coordinates.  Have to be in geographic?
	EXTENT -5038852 3420000 -1412356 5970000
	# Bathymetry.tif extend in geographic coordinates
	# EXTENT -45.26477766016219 29.347893202612525 -12.687409814179109
47.1708141841107

	UNITS METERS
	SHAPEPATH "/data/coverages/zoomazores/"
	IMAGECOLOR 255 255 255
	OUTPUTFORMAT
		NAME png24
		DRIVER "GD/PNG24"
		MIMETYPE "image/png"
		IMAGEMODE RGB
	
		EXTENSION "png"
	END
	WEB
 		METADATA
    		"wms_title"     		"WMSDemo"  			
    		"wms_onlineresource"
	"http://localhost/cgi-bin/mapserv?map=/var/www/mapserver/WMS.map"
    		"wms_srs"       		"EPSG:900913"  				
    		"wms_format"          	"image/png"
  		END
	END
	PROJECTION
  		"init=epsg:900913"
	END
	LAYER
  		NAME "bathymetry"
		# The same extend that the file Bathymetry.tif in projected coordinates.
  		EXTENT -5038852 3420000 -1412356 5970000
		# Bathymetry.tif extend in geographic coordinates
  		# EXTENT -45.26477766016219 29.347893202612525 -12.687409814179109
47.1708141841107
		# Mercator full extend in projected coordinates.
  		# EXTENT -20037508.34 -20037508.34 20035017.34 20035017.34
  		METADATA
    			"wms_title"    "bathymetryshaded"
 		 END
 		 TYPE RASTER
 		 STATUS ON
  		DATA "Bathymetry.tif"
  		PROJECTION
   			 "init=epsg:900913"
  		END
	END
END


Tilecache.cfg
================================
[bathymetryshaded]
size = 256,256
srs = EPSG:900913
type = WMS
url = http://localhost/cgi-bin/mapserv?map=/var/www/mapserver/WMS.map
layers = bathymetryshaded
mapfile = /var/www/mapserver/WMS.map
# bbox = -20037508.34, -20037508.34, 20035017.34, 20035017.34
# bbox = -45.26477766016219,29.347893202612525,-12.687409814179109,47.1708141841107
bbox = -5038852, 3420000, -1412356, 5970000
extension = png
# extent_type = loose
levels = 11
maxresolution = 7083 ## maxResolution = (max-X – min-X) / 512
# maxresolution = 1222.992452344 # google
metaTile=true
tms_type=google
spherical_mercator=true


1 Request URL
================================
http://localhost/cgi-bin/tilecache.cgi?LAYERS=bathymetryshaded&SERVICE=WMS&SRS=EPSG:900913&BBOX=-5038852,
3420000, -1412356, 5970000

# PROBLEM (1)
An error occurred: can't find resolution index for 14166.000000.
Available resolutions are:
[156543.03390000001, 78271.516950000005, 39135.758475000002,
19567.879237500001, 9783.9396187500006, 4891.9698093750003,
2445.9849046875001, 1222.9924523437501,


2 Request URL
================================
http://localhost/cgi-bin/tilecache.cgi?LAYERS=bathymetryshaded&SERVICE=WMS&SRS=EPSG:900913&BBOX=-20037508.34,
-20037508.34, 20035017.34, 20035017.34

# PROBLEM (2)
# The image (SIZE 600 400) that I can visualize in the browser is
white having inside my data in a small really part.



OpenLayers
================================
function init(){
			
	var maxbounds = new OpenLayers.Bounds(-20037508.34,-20037508.34,
20037508.34, 20037508.34);

	zoomBbox = new OpenLayers.Bounds(-5038852, 3420000, -1412356, 5970000);
			
	var options = {
		controls: [],
		maxExtent: maxbounds,
		restrictedExtent: zoombounds,
		projection: new OpenLayers.Projection('EPSG:900913'),
		units: 'metres',
		minZoomLevel:7,
		maxZoomLevel:17,
		numZoomLevels:10,
		maxResolution: 1222.992452344
	};
				
	map = new OpenLayers.Map('map', options);
				
	var tiled = new OpenLayers.Layer.TileCache(
		"teste",
		"http://localhost/cgi-bin/tilecache.cgi?",
		{
			layers: 'bathymetryshaded',
			format: 'image/png',
			srs: 'EPSG:900913',
			serverResolutions: [1222.992452344, 611.496226172, 305.748113086,
152.874056543, 76.437028271, 38.218514136, 19.109257068, 9.554628534,
4.777314267, 2.388657133, 1.194328567],
			tileSize: new OpenLayers.Size(512,512)
		},
		{	
			isBaseLayer: true	
		}
	);
				
	map.addLayers([tiled]);
	map.zoomToExtent(zoomBbox);
}

# PROBLEM (3)
# I only can see transparent tiles, there is not map.


Questions
================================
Is it possible to specify the bbox on projected coordinates in
tilecache.cfg file?

Am I missing something?

It's a good approach?

I think until the MapServer side it's right because it can show the
image on the browser with the following request:
http://localhost/cgi-bin/mapserv?map=/var/www/mapserver/WMS.map&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&LAYERS=bathymetryshaded&STYLES=&SRS=EPSG:900913&BBOX=-3586380.0348868947,4286595.390705814,-2690369.4534918354,4996719.237946053&WIDTH=600&HEIGHT=400&FORMAT=image/png

I tried creating the tiles with the tilecache_seed, specifying the
-bbx option, but I only get withe/transparent tiles.   Its related
with the problem (2) our (3)

Right now I have no ideas on how to solve it and so I feel lost.

I will really appreciate some help.
Thanks in advance!
Oscar