In adjusting SPC distances it is necessary to use a combined scale factor representative of each end.
Therefore it is incumbent to include the combined scale factor at the point of adjustment. Assuming you are adjusting about 0,0 as appears to be so common, the value should come readily to hand.
Paul in PA
Paul...
Not really helpful to the discussion, old friend. A project combined factor is common. Technically speaking what you describe is correct for inverse distances, but not always necessary if the combined factors vary only slightly.
The aim is not to obtain a horizontal surface distance from an imaginary 0,0 to the project.
If You Have No Scale Factor At 0,0, Then You Are Wrong
What I hear being said is "We've done it wrong for so many years that it must be right."
I guess if everybody does it wrong exactly the same way, overall results will be consistent.
It is hard to overcome "STUPID".
It is harder to overcome "GROUP STUPID".
Paul in PA
If You Have No Scale Factor At 0,0, Then You Are Wrong
> I guess if everybody does it wrong exactly the same way, overall results will be consistent.
>
What is it exactly that you are claiming is "wrong", Paul?
To get a proper inverse, you need to consider the combined factor at both ends of the line. Scaling from 0,0 is not done to derive a proper inverse from 0,0 to a point on the project site, it is done to derive near proper inverses from two points with near common combined factors.
It's a sloppy process. But technically it isn't "wrong", is it?
If You Have No Scale Factor At 0,0, Then You Are Wrong
And apparently it's impossible to overcome myopic narcissism...
I'm not sure I am following this discussion.
The scale factor at 0,0 is irrelevant because when you multiply by 0 you get 0.
If You Have No Scale Factor At 0,0, Then You Are Wrong
Shawn: Some time ago, I came on this board with a fairly software-specific question (to which, it turns out, there is not a neat and tidy answer), and you responded with some good advice on the topic and some tips to try in general. I responded to that with a snarky, rude, and impatient reply. I apologize for being a jerk, and I appreciate you sharing your knowledge and advancing the profession.
If You Have No Scale Factor At 0,0, Then You Are Wrong
Man, I'm humbled by that. Water under the bridge. Hope you found a solution to your question.
Sorry, You Are Scaling Distances From 0,0 to Project Site
Multiplying by zero does not cut the mustard.
Paul in PA
Sorry, You Are Scaling Distances From 0,0 to Project Site
Paul,
I'm still not sure what mustard we're trying to cut. Can you elaborate?
If I understand correctly, vern is suggesting NOT to start at 0,0 because ANY scaling value won't apply.
Perhaps better to arbitrarily start at 1,1 then some scaling value would be relevant.
And, If I ain't understandin this here mustard recipe, then by all means toss me out the kitchen!! 😀
In strict terms it is proper to scale distances between SPC coordinates by the average combined factor at each end of a particular line. Using basic algebra it is possible Le to come up with nearly the same distance by computing an average CSF for the project and applying it to the whole coordinate. Another name for that is scaling from 0,0.
The advantage is simple. I can move e back and forth between SPC and ground by simple arithmetic. As long as I stay in a reasonable area (horizontally and vertically) I will be fine. The distortions introduced can be computed with ease.
Some folks can't wrap their heads around the fact that it works. It is incredibly simple and it works. To those folks i say fine, send all the clients requesting tbis type of data to me. You wont need to worry at all...
The advantage is simple. I can move e back and forth between SPC and ground by simple arithmetic. As long as I stay in a reasonable area (horizontally and vertically) I will be fine. The distortions introduced can be computed with ease.
Some folks can't wrap their heads around the fact that it works. It is incredibly simple and it works. To those folks i say fine, send all the clients requesting tbis type of data to me. You wont need to worry at all...
Exactly: if you don't want the work cause you are "offended" by the very thought of using these coordinates by all means then please, please turn down the work, I'll do it!!!!;-)
Sorry, You Are Scaling Distances From 0,0 to Project Site
> Multiplying by zero does not cut the mustard.
>
> Paul in PA
I sense you are trying to make some point here. It escapes me completely.