Does anyone know what kind of Cogo and Drafting software that the BLM uses for their surveys? I know they use true bearings and ground distances on every line, but I am wondering how do you work in that kind of system with modern equipment and software.
For many years it was CMM and ACAD. Not sure if that has changed recently or not.
Jerry has some info posted on Cadastral.com.
http://www.cadastral.com/cadpap2.htm#CMM
> For many years it was CMM and ACAD. Not sure if that has changed recently or not.
> Jerry has some info posted on Cadastral.com.
>
>> http://www.cadastral.com/cadpap2.htm#CMMbr >
About 10 years ago, I tinkered a bit with their GMM program. You could key in all the dimensions from a township plat then enter the coordinates of the known section corner positions and then it would compute the remaining section corner coordinates by least square adjustment along with error ellipses. Wasn't to helpful for me. It seemed like you had to have a good amount of good section corner positions around the corner you were searching for to give reasonable results. Otherwise, the error ellipses were so big that there would be no way to find a corner within it in a reasonable period of time.
I think if I were registered, and making the purchases, there is one company I wouldn't overlook.
CMM is the survey tool for use with the field surveys.
BLM Cadastral many years ago developed special AutoLISP utilities within AutoCAD that allow them to work with projections and also work with geodetic coordinates. Also input, output and annotate in true mean bearings and provide a number other specialized routines to facilitate making official plats but also useful in the field almost like a visual cogo. Alaska uses it's own routines.
Also data collection component was called CEFB that ran on DOS platforms specifically the HP-200lx and is still in use by some. RTK GPS seems to have reduced the demand for a CEFB replacement.
- jlw
> BLM Cadastral many years ago developed special AutoLISP utilities within AutoCAD that allow them to work with projections and also work with geodetic coordinates. Also input, output and annotate in true mean bearings and provide a number other specialized routines to facilitate making official plats but also useful in the field almost like a visual cogo. Alaska uses it's own routines.
>
> Also data collection component was called CEFB that ran on DOS platforms specifically the HP-200lx and is still in use by some. RTK GPS seems to have reduced the demand for a CEFB replacement.
>
> - jlw
Wow... you still have CEFB in circulation? BLM must have bought a shipping container full of those HP-200 palmtop computers. I remember attending a seminar with Dr. Ray Hintz on CEFB back when the Florida Department of Transportation was considering using it for their projects (never really took off). We had a couple of those HP-200's, but they didn't last long in the field. Are those AutoLISP utilities public domain software?