Field Notes
I’m looking for a label for calc’d distances from office-generated coordinates. I normally write, for example, 58.03′ (C) for a distance calc’d from points located in the field. I suppose I could use 58.03′ (F), but that might be confused with a measured distance. Field notes can get crowded quickly when you use a bunch of labels.
- 8 Replies
I have used
M – measured – hands on measurement
CP – calculated – math
C – called from deed
The common designations I’ve seen are (R) for record, meaning numbers on the deed or prior plat and (M) for values determined by measurement during the current survey.
I have also seen (R-1980) and (R-2005), or was it (M-2005), to reference a plat and a retracement that weren’t identical.
Perhaps you would want to indicate (RC) for calculations from record values of things that weren’t given.
If you measure GNSS coordinates on points the distances and bearings between them are still measurements you made and don’t need a different label any more than you need to distinguish chained distance measurements from EDM measurements.
I don’t understand Harris’s C vs CP descriptions.
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If you measure GNSS coordinates on points the distances and bearings between them are still measurements you made and don’t need a different label any more than you need to distinguish chained distance measurements from EDM measurements.
I was wondering, before I posted this topic, if there was a distinction between these. I respectfully don’t agree with you concerning the GNSS coordinates because you’re calculating the distances and bearings between points.
MHYou can’t directly get coordinates. If you break down what the GNSS system is doing to give you those point coordinates, you are really measuring changes in distance from satellites to your receiver and comparing those to changes in distances between the satellites and a base station or CORS. So finding the distance and bearing between two of your points from coordinates is continuing the process of working with distances and directions that has already been happening. Just because you do part of the calculation instead of Trimble or NGS or whoever doesn’t make it any different.
Let’s see what others have to say.
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F: Field – chained
M: Measured – inversed
FM: Filed Map – record per map
D: Deed – record per deed
S: Survey – calculated if different from record.
I agree. GPS is multiple timing based intersections coupled with a baseline to create a least square analysis that happens before you see anything displayed on the screen.
You’re taking coordinates that have been generated by multiple observations that include multiple errors that the software can compensate for on typical observation days.
Now, you’re trusting those results to go from Geocentric to topocentric and go about your local survey.
My rant is that people tend to think gps is the endgame for surveyors. However, it is just another tool. Like all tools, never take it as being gospel.
(I) for inverse.
Right, I managed to get a bad RTK initialization a couple of weeks ago in a marginal situation. It said the monument tied into conventional traverse I was checking is 3′ away (traverse points nearby checked very well but on another initialization), so I dumped the initialization and floating it said the monument is 1′ away LOL.
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