Defining a local coordinate system

[lholt]

The coordinate system currently in use by the City I work for is a ground scale system derived from a State Plane coordinate system based on a Lambert conformal conic projection. The conversion is done by scaling the State Plane coordinates by an average combined grid factor (the City is small & flat so one factor works for the everything) then moving the whole system 1,000,000 ft.
Problem: I want to define this local system so that it can be assigned to a map & conversions of maps on other systems can be done accurately when they are queried in and the track coordinate function can be used. The false northing of the State Plane system is 0.00 so scaling is the problem.
Any ideas?

[mjfarrell]

You will need to use the MAP>>Tools menu item
Define Global Coordinate System
This is where you would enter the details of your Localized
coordinate system.

[lholt]

I have been there, done that. The problem is, I'm trying to match to the existing coorinate system I described. There would be no problem if I were establishing a new coordinate system. I'm searching for a mathematical solution rather than trial & error to solve the problem of scaling the false northing at the origin.

[MHultgren]

I would contact the City Surveyor to find out the settings that are used for the CS. If they want things in their system, they should be able to tell you what the settings should be.