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Lambart Conformal Conic (LCC) & Lambart Tangential Conic (LTC)

May 11 2010 | 1 comment
Categories: Map Data

Hi experts,

I need to convert our spatial data from Lambert Tangential Conic (LTC) to Lambert Conformal Conic (LCC). I came to know somewhere in the net that:

LCC with Standard Parallel 1 (SP1) and Standard Parallel 2 (SP2) are equal and same with central latitude is identical with LTC.

Please confirm if this is true or not. If yes, please let me know whether any mathematical relation exists with SCALE FACTOR in LTC with SP1, SP2, CENTRAL LATITUDE and FALSE EASTING, FALSE NORTHING.

I have SCALE FACTOR, FALSE EASTING, FALSE NORTHING of my existing LTC projection but need to find SP1, SP2 for the LCC. Is that something that can be calculated from scale factor?

Please advise.

Mapping Center Answer:

Lambert conic parameters posted by Melita Kennedy on Jun 2 2010 4:49PM
When working in ArcGIS, it supports two versions of Lambert conformal conic. These are the parameters that are common to both:

central meridian
latitude of origin
false easting
false northing

The two standard parallel case also uses:

standard parallel 1
standard parallel 2

The 1 standard parallel + scale factor case adds:

standard parallel 1
scale factor

In this latter case, standard parallel 1 and the latitude of origin should use the same value. If standard parallel 2 is also listed, set it equal to standard parallel 1 / latitude of origin.

The easiest way to set up your projection definition, is to choose an existing 1 std parallel/scale factor case and then modify it. An example is many of the French systems in coordinate systems\projected coordinate systems\national grids\france.

Melita

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