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NW Ohio | I read your post in the Machinery section as well. The benchmark is supposed to be a physically repeatable position. The monitor will show where it is but that is also dependent on your base. Were you using a permanent base station or did you do a new base here (or average) each time. If a permanent, there will hardly be any difference from your physical location and the location on the screen. If you did a new base when you returned to the field you could be anywhere up to 20 feet off in Lat/Lon and up to 40 feet off in elevation.
For future reference, if you are not already, when creating a new base make the base mount point a truly repeatable location. I use a telephone pole mount or a fence post. When setting up the new base, change the name to something that reflects the job you are doing. We do commercial tiling so I name the base the first four or five letters of the customer name and a number. For instance, customer name is John Smith, I name the base SMITH001. When we return to the job later, we mount the base in the same location (telephone pole/fence post) and Trimble's autobase function recognizes where it is and uses the same base data. It is very similar to a permanent base location only not survey into location. The only issue with this is Trimbles 442/542 bases can only store 12 or 13 bases. When you create a new one and the memory is maxed out, it indiscriminately delete whichever one it chooses. Learn how to use the webuser interface with your base and backup the base data for future use.
Another good practice is after making your Master Benchmark is to make additional benchmarks. Make one on a culvert and another on some other fixed object like the road. I paint an X on each so that it can be used to re-bench if need be. This is similar to the other posts "control points" That is AGPS's name for a benchmark. Same function. | |
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Lost my master benchmark flag for leveling
