Aloha,
I was using Survey Pro to determine a Remove Elevation. I got the measurement. But I do not understand the Zenith reading. I thought if the setup is good my zenith should be close 90º Result of the the Remote Elevation measurement shows 86º17'25" Why is that? What did I mess up? I am wondering if someone can give me quick lesson on this?
Thank you very much.
Yswami
Zenith works with Zero degrees straight up. The horizon is 90 degrees. Your angle of 86-17-25 is 3-42-35 above the horizon.
Do the math with the pieces your instrument is giving you:
9.172 squared + 141.458 squared = 141.755 squared. (rise / hor / slope dist)
or take the sine of your Zenith angle, times slope to get the horizontal, or cosine of zenith time slope to get the rise.
After trying that is it more clear?
I have been watching your posts and you have made great strides to understand some of what we do - keep it up!
Ken
Hello yswami,
This is a pretty easy one. Zenith angle is your measured angle from directly above, which has a back-sight angle of zero. Take the Cosine of your Zenith angle multiplied by your slope distance should give you the vertical difference which is added or subtracted from your station elevation. Of course,you have to add in your Instrument Heights and subtract your Rod Heights. Usually, the software handles all this for you. Hope this is been of some help to you.
Aloha.
Mapman
> Yswami
>
> Zenith works with Zero degrees straight up. The horizon is 90 degrees. Your angle of 86-17-25 is 3-42-35 above the horizon.
>
> Do the math with the pieces your instrument is giving you:
>
> 9.172 squared + 141.458 squared = 141.755 squared. (rise / hor / slope dist)
>
> or take the sine of your Zenith angle, times slope to get the horizontal, or cosine of zenith time slope to get the rise.
>
> After trying that is it more clear?
>
> I have been watching your posts and you have made great strides to understand some of what we do - keep it up!
>
> Ken
Aloha, Ken:
Thanks for explanations. Yes the simple trig. help me to understand it better. For some reason when I mentally visualizing it, I was visualizing the Zenith tilting when I saw the 86º angle. Now I seen it is angle of SD and the Zenith! Duh!!
Every single stride I've made so far in this area I'd fully attribute to generous folks like you on this forum! For which I can't thank enough!
Aloha, Doug:
They say a picture worth thousand words. You just proved it to me!
Thank you.
> Hello yswami,
> This is a pretty easy one. Zenith angle is your measured angle from directly above, which has a back-sight angle of zero. Take the Cosine of your Zenith angle multiplied by your slope distance should give you the vertical difference which is added or subtracted from your station elevation. Of course,you have to add in your Instrument Heights and subtract your Rod Heights. Usually, the software handles all this for you. Hope this is been of some help to you.
> Aloha.
> Mapman
Aloha, Mapman:
Yours and Ken's explanation with Doug sketch did it! As always thank you for sharing your knowledge.
Aloha.