I know about the ASPRS standards for aerial, UAS, and LiDAR but is there a formal standard on point spacing for traditional surveys in relation to contour interval? I was once told to use open areas 50' spacing for 2' contours and 25' spacing or less for 1' contours. Thoughts?
Thanks
Back in the day, we would layout a 50' grid, for most topo's, and tape in the breaks and features. Some clients would require a 25' grid, but we considered that an over kill.
Today, with modern survey equipment, it's more important to pick up the breaks and fill in the other areas with enough shots to pull all the tin lines together.
When I'm doing a topo, today; at every shot I take; I look at the other shots I've taken, and the shots I'm going to take. Pick up low spots, pick up high spots and don't worry so much about spacing.
Anyone that lays out a baseline or grid is wasting their time. Let the ground guide you.
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That is a guideline which I would generally agree with. However, I know of no particular standard for this sort of thing. Any such standard would have to make allowance for breaklines.
Oregon DOT procedure is to test the DTM with separately collected spot elevations for conformance with specifications for paved, graded, natural, and rugged surfaces.
As ususl, it depends...
The complexity of the terrain, vegetation cover and use of the topo will drive the method and density of data collection.?ÿ
Grid patterns work well for flat areas with little relief. I wouldn't lay the grid out unless it served multiple purposes. The end user may need the grid lines for cuts and fills, geotech work or any number of other uses.
The main thing is to map the breaklines and other key feature changes.?ÿ It grates on my nerves to be handed a topo showing no jump at curbs and continuing through solid buildings (that may have a basement. lol) or jumping across obvious ditches.
Thanks, this is all what I figured, I was specifically talking about open areas, fields, etc. Breaks are of course needed.?ÿ
This discussion of grid patterns brings something to mind.
Survey techs I work with favor turning on the ground shot point layer, with an elevation only label, and populating the drawing with spot elevations that way.
I favor putting a few spot elevation labels per the DTM in places where it is visually appealing (such a high and low points)
You are correct; they are not. Aesthetics > Ease of Workflow
I hired a guy one time who claimed he had 18 months experience.?ÿ It turned out he had one month's experience, if that, 18 times.
We were to topo a rolling field at an airport for future parking, about 12 acres.?ÿ There wasn't a lot of relief, maybe five feet between high and low points.?ÿ I figured we best layout a grid since I wasn't sure he knew where to take shots.?ÿ I put a paint dot every where I wanted a shot. I planned on reading the rows boustrophedonically. I told him to start at one end and walk north and put the rod on every dot and I would wave him off when I got the shot.?ÿ When he got to the end of the row he asked what to do next.?ÿ I told him to move over to the next line and go south.?ÿ When he got to the end he asked again what to do next, and did so at the end of every row.?ÿ About halfway through he asked, "Since you're not gonna hire me ever again, what are you paying me for today?"?ÿ That was the only thing he got right that day.
