EPSG code for...

[Christopher R. Thorne]

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
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