Connection between GPS coordinates and local coordinates.
Hello!
I am doing a survey.
I have a big property drawn in AutoCAD.
Could you please help me understand how to convert coordinates from the AutoCAD local coordinate system to UTM coordinates that I have to put in my TSC7 controller?
For example, I have a point with coordinates received with R12i:
Northing 5344222.851
Easting 605605.481
I know that the point of interest #40 is located at 3,909.080 m and bearing N82d24'23"W away in the local coordinate system.
What are the coordinates of point #40?
You need a point in the local system that has a known UTM coordinate. Without that you only have 2 coordinate systems that have no relationship to each other.
Use the Cogo functions in the TSC7
You want to 'Compute a point' by 'Bearing and Dist'
Select your point
Key in the bearing and distance
Formatting the bearing value can be a pain, but if you set the job units up right - see the Job Properties - you can key it directly.
There is also a calculator available for conversions etc - check the triangle menu on the fields
I have a point in the local system. It has known UTM coordinates, but local coordinates can be any. Let's say (0,0).
Thank you.
TSC7 is a pain point as I rent it.
Do not use 0,0 for any local point. That will send you into all four quadrants with positive and negative coordinates.
There are a number of ways to relate the coordinates but why bother, find your UTM number and stick with them, move your figure calculated in autocad to the UTM position. The command is M. All you need to do after that is figure out the rotation from your calculated figure to UTM grid. Depending were you are in the zone it can be a minimal rotation or a multiple degree rotation. That can be easily figured out in Trimble for an astronomic to grid rotation, but when you locate actual monuments it will probably be slightly different. Keep your figure as a block, you can even copy, it move it, block it and wait until your rotation information is determined before exploding it.
As far as new coordinates from a position it's a simple formula:
If you have a calculator for the above example it's
easting=605605.481-(sin of bearing x 3909.08)=601730.683
northing=5344222.851+(cos of bearing x 3909.08)=5344739.420
Checkbook math. If you want to dig deep into UTM you will need to geodetically calculate latitudes and longitudes forward and then convert to UTM, but that's not necessary for small projects like this one.
You can set your UTM zone in Autocad and then you will have lats, longs, Northings, Eastings, all available in Autocad and Trimble. Makes for easy checks between the databases.
Be careful here. Are the coordinates that you gave us UTM or local coordinates? If the coordinates are UTM and the bearing and distance are on a local coordinate system, then calculating the the coordinates of Point# 40 can't be done from the given information.
Is that why you asked the original coordinate conversion question?
I gave UTM coordinates initially and this was exactly the nature of my question. How to calculate UTM coordinates of the point #40 using local distance and bearing?
Thanks a lot for lot of info. Trigonometry is easy. I feel like whatever I do, I will have to dig around a while before I find something.
I have R12i in possession now but lack of experience of working with it. AutoCAD is way easy. Not sure about the trsult now. I will keep you posted.
Thanks again.
I need #40 coordinates to find it in forest.
