EPSG code for...

[Christopher R. Thorne]

Dean,
thanks for the information. unfortunately it did not work out. I managed 
to overlay the data sets on top of each other using NAD83 with WGS84 and 
  projected to 4326, there is still a southeast shift by a few hundred 
meters. When using NAD27 it was no good.


I have basically given up, until I find a better GIS tools to figure out 
what is going on.

Thanks again,
Chris

Dean Mikkelsen wrote:
> Sorry, a bad typo. MTM applies to Canada, not the US.
> 
> Cheers,
> Dean
> 
> ----- Original Message -----
> From: Dean Mikkelsen <dcmikkelsen at SHAW.CA>
> Date: Tuesday, June 14, 2005 9:10 am
> Subject: Re: [UMN_MAPSERVER-USERS] EPSG code for...
> 
> 
>>Hi again,
>>
>>MTM is defined for Canada. They are 3 degree Modified Transverse 
>>Mercator projections. They will not apply to Canada.
>>
>>For a reference see the following web-sites:
>>
>>MTM:
>>http://www.geod.nrcan.gc.ca/images/products/MTM.jpg
>>
>>UTM:
>>http://www.geod.nrcan.gc.ca/images/products/UTM.jpg
>>
>>Both were referred to via:
>>http://www.geod.nrcan.gc.ca/index_e/online_apps_e/appNtv2_e/appntv2_utm_e.html
>>
>>Cheers,
>>Dean
>>
>>
>>
>>----- Original Message -----
>>From: "Christopher R. Thorne" <christhorne at SYMPATICO.CA>
>>Date: Tuesday, June 14, 2005 7:36 am
>>Subject: Re: [UMN_MAPSERVER-USERS] EPSG code for...
>>
>>
>>>Hello me again,
>>>I finally tracked down the metadata for the data that was given 
>>
>>to 
>>
>>>me 
>>>with the strange projection. Well it gets stranger. Here is what 
>>
>>I 
>>
>>>found. I have two shape files of the Los Angeles county
>>>
>>>1st shape file :
>>>----------------
>>>Datum:NAD27
>>>Units: Meters
>>>Ellipsoid:Clark 1866
>>>Projection: UTM, Zone 11
>>>
>>> * Possible EPSG codes found:
>>>
>>># NAD27(76) / MTM zone 11
>>><2020> +proj=tmerc +lat_0=0 +lon_0=-82.5 +k=0.999900 +x_0=304800 
>>>+y_0=0 
>>>+ellps=clrk66 +units=m +no_defs  no_defs <>
>>>
>>># NAD27 / UTM zone 11N
>>><26711> +proj=utm +zone=11 +ellps=clrk66 +datum=NAD27 +units=m 
>>>+no_defs 
>>> no_defs <>
>>>
>>>2nd shape file:
>>>
>>>Datum:NAD83
>>>Units: Meters
>>>Ellipsoid:Clark 1866
>>>Projection: UTM, Zone 11
>>>
>>>  * Possible EPSG Codes found:
>>>
>>>  NONE FOUND.....
>>>
>>>This makes me think that NAD83 with a Clark 1866 Ellipsoid is 
>>
>>not 
>>
>>>a 
>>>valid projection. Am I on the right trake of thinking or is 
>>
>>there 
>>
>>>actually an EPSG code with:
>>>
>>><????> +proj=utm +zone=11 +ellps=clrk66 +datum=NAD83 +units=m 
>>>+no_defs 
>>>no_defs <>
>>>
>>>Comments?
>>>Chris
>>>
>>>Christopher R. Thorne wrote:
>>>
>>>>Hello Dean,
>>>>
>>>>Dean C. Mikkelsen wrote:
>>>>
>>>>
>>>>>Hi Chris,
>>>>>
>>>>>Take a look at the following web-page.
>>>>>I am leaning towards a problem now in defining which State Plane
>>>>>Co-ordinate System is being used. i.e. one of the ones we are 
>>>
>>>using is
>>>
>>>>>wrong - we may actually be north or south of the current one. 
>>>
>>>Now the
>>>
>>>>>trick is to determine which one. A note to other readers 
>>>
>>>epsg:4326 is
>>>
>>>>>WGS84.
>>>>>
>>>>>Did you try reprojecting the NAD27 Layer with the NAD83 
>>>
>>>definition? 
>>>
>>>>
>>>>Yes I did that and the layers switched positions.
>>>>
>>>>Or
>>>>
>>>>
>>>>>with epsg:4326? What happens?
>>>>>
>>>>
>>>>with setting the projection to the lat/long layers, they are 
>>
>>not 
>>
>>>found 
>>>
>>>>in outer space, not within the world extent.
>>>>
>>>>
>>>>>http://www.wadetrim.com/resources/articles/sblocks.htm
>>>>
>>>>
>>>>Thanks for the good reference. The reason why I got into this 
>>>
>>>situation 
>>>
>>>>was because I am four steps removed from the data provider. I 
>>>
>>>only 
>>>
>>>>managed to get the information that you already know and I was 
>>>
>>>hoping 
>>>
>>>>the information was correct. The other problem was that I was 
>>>
>>>not sure 
>>>
>>>>how to identify the issues, confidently. If not I will 
>>>
>>>definitely push 
>>>
>>>>for more information.
>>>>
>>>>Cheers and thanks again,
>>>>Chris
>>>>
>>>
>>>
>>>-- 
>>>Christopher R. Thorne, GIS Specialist
>>>-
>>>christhorne at sympatico.ca
>>>Tel:(613)523-6593, Ottawa ON Canada
>>>-----------------------------
>>>
>>
> 


-- 
Christopher R. Thorne, GIS Specialist
-
christhorne at sympatico.ca
Tel:(613)523-6593, Ottawa ON Canada
-----------------------------