Sometimes You Just Get Lucky
This morning I returned to a topo project that I started early last week, and promptly set the robot up on the last control point I had set. However, it wasn't until I was all set up that I discovered that the control point wasn't in the DC - somehow it didn't get recorded. There's only one other control point visible from the setup, but I was going to have to traverse anyway, so I decided to use the setup and fix it in the office later. There was a DI about 20 feet east of the setup that I had shot last week, so I copied the DI point to create the setup control point, changing the easting by 20 feet and raising the elevation a couple of tenths. I walked over to the backsight point and zeroed on it, and when I checked the backsight screen I saw this:
Not bad for an eyeball job.
But better yet, when I later closed on another control point I only missed by 0.09'.
I wish I could attribute this to superior expertise, but I think sheer dumb luck played a larger role.
Frame Surveying & Mapping
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Davis, CA 95616
I use my Pocket Silva Ranger to get a bearing for the first backsight, just to be roughly close (nearest 2 degrees).
It is surprising how often StarNet will report the Silva Ranger bearing is within a few minutes of reality.
O death, where is thy sting? O grave, where is thy victory? -1 Corinthians 15:55