I recently been sent some shapefiles that are in NAD27 and the projection to NAD83 I am using does not match the output of the bearings and distances from the NAD27 file. I heard using the transformation NADCON is the best transformer. Anyone out there know best to convert these shapefiles?
The additional information is helpful. You're correct that NADCON, specifically its CONUS (contiguous/continuous US) grid file. In ArcGIS, that's the NAD_1927_To_NAD_1983_NADCON transformation. Because NADCON is a piecewise method (in a way), bearings and distances won't be the same. To get those corrected, you would probably have to have a surveyor re-adjust/resurvey the data.
This data was collected by GPS and the points sent to me were in NAD27 Stateplane Montana South. What I have discovered when the connect the points to create lines they can determine the bearings and distances, however the bearings do not match. What I am also finding out is that they create the transformation after they lines are generated and that data is sent to me. What I have now done to correct these errors is to have them send me the points in NAD27 and I will do the re-projection to NAD83 stateplane FIPS feet, but what is needed is the right transformation. From there I can create the lines and then open up the traverse tool and click editing and have the transverse data captured from by loading travers from sketch. That way I can send him back this data through a save traverse file and he can send me back the survey. Fun huh!
P.S. Read the paper I submitted to the 2012 International Conrference on the topic of 3D titled "To 3D or not To 3D" how Jack has convinced us that the world is flat again.