Can horizontal distance be bigger then slope distance??
When and why? please see attached.
This is a raw slope distance, whereas the horizontal distance is computed (I assume this means reduced).
See page 10:
I'd also add the Slope (raw) does not account for things like the prism constant. If you change your prism constant within TBC you'll see this Slope (raw) stay the same where your horizontal distance will change.
Your raw slope distance of 203.769 m doesn't jive with the computed vertical distance of 1.224 m for a vertical circle reading of 89-41-42.
Using your vertical reading and the computed vertical distance to back calculate slope gives 229.936 m, so a good bit longer than your raw measurement.
I would suggest you double check your prism constant as well as your target and instrument heights.
Edit: Actually the computed vertical distance should be the difference between the elevation of the instrument and target points on the ground, so my calculation wouldn't account for the difference in instrument and target height and therefore the longer slope I calculated wouldn't be correct. Basically we would need your instrument height to do a full check, but as someone else pointed out, the raw distance doesn't account for prism constant, so that's most likely the reason for the longer horizontal distance.
To verify, if I back calculate your instrument height from the available information I get 1.361 m:
delta(h) = (slope*sin(90-VA))+HT-HI => 1.224 = (203.769*sin(0-18-18))+1.5-HI => HI = (203.769*sin(0-18-18))+1.5-1.224 = 1.361 m
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