I think a BASIC course in SPC, Projections, and bearings, and the actual math behind going from ITRF, to Lat Lon, to a particular projection, then how to get ground coords, and then how to catch more fish!
Is there a good book on this?
Also, somebody suggested a seminar on Surveying and the Bible.
Deriving coordinates that are as right as possible, and deriving a good data flow, for "Be fruitful, and multiply, and replenish the earth, and subdue it:" (pursuant to Genesis 1:26-28)
That would be interesting!
Need to fish more!
Nate
Nate, you need to consult with my retirement planner "Fishmore and Dolittle"
I will be attending more continuing ed for SPC, projections etc. Us old timers have to try and keep up with these tech savvy young bloods!
The good thing about continuing ed is getting out and talking to fellow surveyors...... The bad part is the cost. Always somebody wanting in the working man's pocket!
Many fewer required hours.
Flame on!
> I think a BASIC course in SPC, Projections, and bearings, and the actual math behind going from ITRF, to Lat Lon, to a particular projection, then how to get ground coords, and then how to catch more fish!
The math to convert Lat/Long to SPC is layed out in this NGS Manual, around pg 40, et seq.
> Is there a good book on this?
GPS for Land Surveyors 3rd Edition, by Jan van Sickle.
While you are waiting for that to arrive check out this from Caltrans.
There is a wealth of stuff available for the googling on the web. Try this, for example
> Also, somebody suggested a seminar on Surveying and the Bible.
I should think that that is one seminar you would be well qualified to teach.
Amen.
Also an end to pre-approved courses.
With you all the way!
Thanks Mr Oklahoma.
I want to think it through, and then get my data flowing...
N
Relevant information and rambling on the topic of presenting complex information at convention workshops.
Recommended free info:
http://www.ngs.noaa.gov/CORS/Articles/FIGSoler.pdf
http://mathworld.wolfram.com/EulerAnlges.html
http://www.unoosa.org/pdf/icg/2012/5_3.pdf
First link is by Dr Tomas Soler of the US NGS detailing transformations from ITRF to NAD 83.
Second link describes the mathematics of the rotation matrices involved in rotating coordinates.
The final link is by Nic Donnelly of New Zealand's LINZ wherein he details how users can transform from ITRF to local reference frames.
Many issues related to OPUS data use are presented in accessible detail in the ASCE publication "CORS and OPUS for Enginners: Tools for Surveying and Mapping Applications" edited by Tomas Soler, PhD. It's ISBN is: 978-0-7844-1164-3.
Now the rambling, entirely avoidable part...
The mathematics underlying these operations is not what I would describe as basic. Though fundamentally we can derive the equations for the new coordinates of a point after we rotate the coordinate system though basic trig identities (the sine and cosine difference identities) and some algebraic substitutions.
Putting the equations in matrix form certainly makes it easier to follow but assumes the user knows how to manipulate vectors and matrices.
When I presented this material to upper-level undergraduates their eyes would glaze over. I can only imagine presenting it to surveyors only there to get their continuing education hours.
The issue of how to convert XYZ coordinates to latitude longitude and ellipsoid heights in a specified ellipsoid is well studied. Even today there are attempts to improve the efficiency and accuracy of the process. There is even research into an improved tri-axial ellipsoid.
The geometry involved in these operations is not basic either. Remember that at a point of interest the normal to the ellipsoid when extended to the spin axis does not intersect with the origin. Our XYZ coordinates are with respect to the origin. We must do approximations and iterations to solve for the geodetic latitude and ellipsoid height.
It is interesting to consider, e.g. the determination of an ellipsoid height at a point given to only its XYZ in a specified ellipsoid. Draw a picture. Remember a point's geocentric and geodetic latitudes differ.
Take a look at the lecture notes of Jekeli and Rapp. Not basic stuff.
What can be achieved in an all-day seminar? What level of insight is achievable or desired? Is knowing that a geodetic and geocentric latitude differ enough insight for a practicing surveyor?
