What is Local Prime Meridian ?

Question

I do not mean the Greenwich Meridian.

Answer 1

Prime meridian for India (IST) is 82 1/2 degrees, corresponding to

+05:30 hrs from GMT

Answer 2

Greenwich is THE prime meridian.  I know of two local meridians.  One is near the border of Los Angeles and San Bernardino counties in California.  The other is in Phoenix AZ.  There are others, but I don't know where they are.

These local Meridians were established by a great land survey done of the western U.S. early in the twentieth century.  The meridian is established parallel to a certain line of longitude.  It is perpendicular to a "baseline"  which runs parallel to a certain line of latitude.

The point where the baseline and meridian cross is called a benchmark.

Definitions of property boundaries are based on these, and references to them can be found on many deeds and titles.  Even if the base line and meridian are not specifically named on a deed, there is survey information that can be traced to them.

You can find the So. Cal baseline by google Eartining "Baseline Street San Bernardino".  I believe (but am not sure) there is a Meridian Ave in Phoenix.