DULLES AIRPORT

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DULLES AIRPORT

Postby DAVID MAYNE » Wed Oct 29, 2003 3:53 pm

I AM TRYING TO CHANGE THE PRIME MERIDIAN IN A GEODETICALLY REFENCED SYSTEM. IT IS A SINGLE POINT SECANT PROJECTION WITH THE REFERNCE MERIDIAN FOR THE CARTESIAN COORDINATES HAVING A GEODETIC AZIMUTH OF 0D39' 3.2894"

THE BASE POINT IS N 38 56 20.66066" W 077 27 35.212096" AT -38.7' NAVD 88.
I HAVE GENERATED A SOLUTION IN XCEL USING A GEODETIC INVERSE FOR S AND FAZ AND ROTATING BACK TO THE THE REFERNCE MERIDIAN.

IT IS ONLY CAPABLE OF A SINGLE POINT AT A TIME AND I WOULD LIKE TO FIND OUT HOW TO DEFINE THE COORDINATE SYTEM WITH THE SKEWED MERIDIAN USING MSCAD.

:?
DAVID MAYNE
 

Airport job

Postby Glen Cameron » Thu Oct 30, 2003 6:46 am

I am not 100% sure what you are asking MSCAD to do. We can rotate a job or portion of a job, we can scale or shift point as well. We even have a routine to convert from one UTM coordinate system to another. We do not have a routine to convert from Ground coordinates to Grid Coordinates or visa versa.

What specifically are you applying to the point(s) to do the conversion in Excel? Maybe we can do the same thing, one step at a time, to the entire point set, if I knew what you were having Excel do.

Cheers,
Glen W. Cameron, C.E.T.
City of North Bay, Ontario
Glen Cameron
 
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Postby Scott Partridge » Thu Oct 30, 2003 8:58 pm

I believe that what David wants to do is create a custom projection with the central meridian to be along the geodetic azimuth he has given passing through the base point provided.

Custom map projections like this can easily be done with many other applications designed for the purpose; Blue Marble Geographic Calculator is one, Trimble Geomatics Office is another, Excel is another (with effort).

I am prepared to be corrected, but I think this is beyond the current functionality of MSCAD. In that event, you would have to do the coordinate transformation from the current projection to the custom one in another app (like Excel), then import the results into MSCAD for drawing prep.

Am I close?
Scott Partridge
 
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