National Atlas Projections... driving me crazy!

[Tyler Mitchell]

Hi Kelly,
I'm not familiar with your national atlas specific projections, but  
do you have more details about the LCC projection you are referring  
to?  LCC is a general class of projection that will have some more  
localised parameters depending on, generally speaking, where you are  
centering your map.  The lat_0/1/2 and lon_0 values might change  
depending on where you are doing your mapping.

Do you already know the more full description of the LCC projection  
you have in mind?

Tyler

On 24-Jul-06, at 6:49 PM, Kelly Koehn wrote:

> I've been working with mapserver for quite some time now and I  
> thought I'd made some strides in the areas of projections but I  
> seem to have went into it all backwards.  I started out with the  
> National Atlas datasets for counties and states.  I've come to the  
> conclusion that the projection they want you to use is 'latlong',  
> ellps is 'GRS80', and datum is 'NAD83'.  The names are 'statesp020'  
> and 'countyp020' I believe.
>
> This is all fine and dandy except unless you project the map as LCC  
> it seems to be vertically challenged.  For instance, the county  
> that I live in (Sedgwick, in Kansas) is not a rectangle.. its  
> square.  I've found some examples of the lat/long to LCC projection  
> but most seem a bit foggy.
>
> My real question has to do with the whole 'lat/long to meters'  
> conversion and how to make heads or tails of the 'cs2cs' program  
> that supposedly converts the values.    Is there some magic trick  
> to this program that I'm not finding?
>
> I have some other questions about exactly what the lat_0, lat_1,  
> lat_2, lon_0 values should be for the LCC projection but I'll save  
> those for another time.
>
> Any help would be great! I'm about ready to rip my hair out!
>
> Kelly
>
>

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