Converting NAD83 to lat/long?

[bandit957]

Does anyone here know the formula for converting NAD83 coordinates to latitude and longitude in degrees? The Internet doesn't seem to have it.

[corco]

NAD83 is just a datum, not the projection so NAD83 could be in lat-long or something else. What do the coordinates you have look like?

[bandit957]

NAD83 is just a datum, not the projection so NAD83 could be in lat-long or something else. What do the coordinates you have look like?

For a certain point within the city of Cincinnati, the X and Y coordinates are 1404800 and 450892.1875. I'm using a list of points within the city of Cincinnati.

[corco]

Okay, they're state plane then. Two ways to do it:

One by one: http://www.earthpoint.us/stateplane.aspx
1404800 is the X, 450892.1875 is the Y, the zone you want is 3402 Ohio - South and the units in US survey feet.

Batch: http://www.earthpoint.us/batchconvert.aspx
and then follow those instructions

The math to do it yourself in Excel gets to be pretty tricky- conceptually I understand how it works, but to actually devise the formula I'm not even entirely sure how to do it.

[PHLBOS]

This site has downloadable programs that allows one to convert state plane coordinates to lat/long & vice-versa.

[Roadrunner75]

This site has downloadable programs that allows one to convert state plane coordinates to lat/long & vice-versa.

I use Corpscon at work for conversions, which is a free download on that site (NGS).  It's easy to use and works well.