[MAPSERVER-USERS] cs2cs problems

Tue Mar 18 08:52:28 EDT 2008

Hi,

I feel we are getting closer to common understandment.  First, for my mind you exactly _do_ want to reproject your data, even if just on-the-fly from epsg:23030 to epsg:4326.  I do not know what projection you need to use with Google Earth but let's hope that epsg:4326 is correct.

Mapserver is doing re-projection for you if you first tell it in LAYER the original projection of the data, and in the MAP level the output projection.  Now I suppose your LAYER is ok if you have set the projection to +init=epsg:23030.

I have never heard about using cs2cs for setting Mapserver projection but it does not prove that it is not possible.  The methods I have used are using epsg code like    "init=epsg:4230"  or proj4-strings. The usage of the projection strings is explained here:
http://mapserver.gis.umn.edu/docs/reference/mapfile/projection
Another document to look through is:
http://mapserver.gis.umn.edu/docs/howto/wms_server

I have to say that it was not very easy to find a document describing promptly how to use Proj4 strings in mapfile, even that possibility is often mentioned in discussions.

-Jukka-

________________________________

	Lähettäjä: CARLA FERNANDEZ [mailto:carla.fernandezb at gmail.com] 
	Lähetetty: 18. maaliskuuta 2008 14:15
	Vastaanottaja: Rahkonen Jukka
	Kopio: mapserver-users at lists.osgeo.org
	Aihe: Re: [MAPSERVER-USERS] cs2cs problems

	Hi Jukka,

	Thanks very much for your interest!! and sorry for the conflicting information...

	I explain you, I have all my layers in epsg:23030, and I don't want to reproject them. However, I want to set my WMS in WGS84-epsg:4326 (not ETRS89-epsg:4230, sorry), so that I can load my WMS in Google-Earth without the difference that it has (almost 130 meters) because of the differents reference systems...It seems like MapServer ignores the projection settings in the map section!! (because I set WGS84, like GoogleEarth)

	And googleing I've read that I can use the cs2cs in the projection object (map section), but I get this error:
	msProcessProjection(): Projection library error. projection not named

	I've tried several combinations, but nothing works...

	PROJECTION
	 #"cs2cs +from +proj=utm +zone=30 +ellps=intl +units=m +no_defs no_defs +to +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs no_defs"
	 "cs2cs +from +init=epsg:23030 +to +init=epsg:4326"
	 #"init=epsg:4326"   
	END 

	Thanks!!

	2008/3/18, Rahkonen Jukka <Jukka.Rahkonen at mmmtike.fi>: 

		Hi Carla,

		Please remember to use "reply to all" in order to send your message for the mailing list as well.  

		 I hope I understand this  correctly. So your original data (the shapefile) is in epsg:23030? Then you should have in mapfile, in corresponding LAYER section

		PROJECTION
		"init=epsg:23030"
		END

		Next, because you are willing to deliver that layer through WMS in epsg:4230, it is good to add this to layer METADATA as 
		"wms_srs"    "EPSG:4230"

		By looking at my old mapfiles wms_srs metadata seems not to be compulsory if WMS service will only be used in one output projection which is the same as the main MAP projection.  Anyway I believe it would be good habbit to have it.

		Third, you should give the default output projection in MAP section as
		PROJECTION
		    "init=epsg:4230" 
		END

		And last calculate the bounding box containing your data in the mapfile projection (epsg:4230) and feel in the values as EXTENT of the map object.

		I try to read your messages once again faithfully and I feel you are giving a bit conflicting information. In one place you say you are willing to publish your data in ETRS89, wich I believe to mean epsg:4258.  If this is the case then insert that value to "wms_srs" and mapfile projection instead of 4230.  Why do you play at all with epsg:4230 if your data are not using it, and you don't want to any output in that projection either?  Perhaps I have just not understood what you are aiming at, but I hope you will have luck with it.

		-Jukka Rahkonen-

________________________________

			Lähettäjä: CARLA FERNANDEZ [mailto:carla.fernandezb at gmail.com] 
			Lähetetty: 18. maaliskuuta 2008 11:50
			Vastaanottaja: Rahkonen Jukka
			Aihe: Re: [MAPSERVER-USERS] cs2cs problems

			Thanks four your answer,

			I've defined projections in my WMS before without problems. In this case I want to change the projection of my WMS (to ETRS89) with the layers in ED50, but if I just set the projection of the header's mapfile like ETRS89, and I leave the  layers' projections like ED50, it doesn't work :( 

			Do you have any idea of how can I use the cs2cs??

			Thanks!!

			2008/3/17, Rahkonen Jukka <Jukka.Rahkonen at mmmtike.fi>: 

				Hi,

				I you want to define projections in mapfile then there are two alternatives:
				either give the espg code:

				PROJECTION
				          "init=epsg:2393"
				END

				or proj4 strings:

				PROJECTION
				"+proj=tmerc +lat_0=0 +lon_0=27 +k=1.000000 +x_0=3500000
				+y_0=0 +ellps=intl +towgs84=-90.7,-106.1,-119.2,4.09,0.218,-1.05,1.37
				+units=m +no_defs"
				END

				But perhaps you are aiming at something else by using cs2cs?

				-Jukka Rahkonen-

				-----Alkuperäinen viesti-----
				Lähettäjä: mapserver-users-bounces at lists.osgeo.org puolesta: cfb
				Lähetetty: ma 17.3.2008 15:49
				Vastaanottaja: mapserver-users at lists.osgeo.org
				Aihe: [MAPSERVER-USERS] cs2cs problems

				Hi,

				I'm having problems with the projection again. I've got a shape in
				epsg:23030 (ED50 UTM 30N), but I want to set my service in epsg:4230
				(ETRS89). I've changed the extent, the "wms_boundingbox" and the
				"wms_latlonboundingbox" of my header's mapfile to geographic coordinates
				(epsg:4230 for ED50), and in the projection object (always in the header, in
				the layer object I leave epsg:23030) I put:

				PROJECTION
				   'cs2cs +from +init=epsg:4230 +to +proj=4258 +no_defs +no_defs +no_defs
				+no_defs +ellps=GRS80 +datum=ETRS89 +no_defs +units=m'
				END http://www.nabble.com/file/p16092875/epsg epsg

				For the second reference system, I've also tried with "+proj=longlat" and
				with "+init=epsg:4258", but I get always the same error:

				msProcessProjection(): Projection library error. projection not named

				The epsg file of my proj4 is attached (ms4w v. 2.2.7, MapServer 5.0.2)

				Thanks in advance!!

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