I’m new to land surveying and have been booking total station data, but electronic data capture makes sense just to reduce the chance of data transcription errors. The few data collector software packages I’ve looked at all require that each shot be stored as a unique point number. Like everybody else I routinely take multiple shots on targets, especially traverse points and I want to have all the data available for post-processing. I may decide which shots to use in the field, but make a different choice back in the office. The packages I’ve looked at do allow multiple shots on the same point and allow inspection, rejection and reshooting, but ultimately force you to average them into one data set for the point; all the individual shots are not available for downloading. I believe some packages offer a work-around where you enter an alias in a code or description field like = so that multiple data collector point numbers get treated as the desired single point number by office software. Problem is I have to stick with a Carlson 2006 office program and find an older DC to keep costs down. While Carlson 2006 allows multiple RW5 file records to have the same foresight point number I don’t believe it will automatically process a file imported from a DC to implement that work-around.
So with all that said, I’m looking for a DC and software that does store all the shots on one point so they are available for download. Does such a combination exist or is there a technique that will work for me?
Since you asked, yes, the Leica allows multiple shots on one point and averages them automatically. It also displays a warning if any shot is outside tolerance. I always take five shots on any control point (it's the same as the carpenter's measure twice, cut once.)
What I do with GPS RTK when I have a point that I want to shoot multiple times for whatever reason is store each shot as 421a, 421b, 421c, ect. I can average it later and store that point as 421 or I can select the point I like and change the point number removing the leter.
That may work for what you want if you have a data collector with alphanumeric points.
James
Trimble also allows multiple observations of the same point, and all of the individual observations are available to download. The trick would be to find a raw data export option that Carlson likes, but Trimble can output SDR and I believe they have style sheets that will create RW5 and FBK.
If you need to buy some thing used for cheap I'd recommend a TSC2 with either Survey Controller 12.41 or Trimble Access running on it.
Hi Bob,
Like you correctly said in your post - the RW5 file contains all the raw observations you took in the field. Including those shots that you took as "repetition" shots (or whatever your data collection software calls them.)
While it is true the Data collector will melt all those down into a single observation, and ultimately into a single coordinate, you are not forced to use that single composite observation.
Download the RW5 file and comment out the composite observed shots.
then un-comment the individual shots that appear in the file immediately above the reduced observation.
It takes time to get comfortable with the language being written to the RAW file, but it eventually becomes second nature.
You'll be bringing in those repeat observations as individual side shots in no time.
Depending on the office software you are using, this type of operation will provide the best set of data to run a Least Squares analysis, by providing ample redundancy, and ample residuals.
Craig
Taking shots of the same point repeatedly is in my opinion a waste of time. Most TS/GPS today can tell you if you are out of vertical while taking the observations.
It is more important to measure the same point after a loop or to check-in on a certain cp from another loop. This is were you are able to get a positional error comparison.