Whenever we get a request for topo on a very short grid request, it reminds me of the old show "Name That Tune".
I think to myself, I can topo that with X shots, well placed shots with breaklines is far more important than just some random grid.
After a very good surface is generated, I can deliver as many "shots" as anyone would want.
Just my 2 cents.
If there is a topo grid that dense, I don't understand why contours are even necessary.
A major fast food giant required a 20' grid plus breaklines. Sometimes 0.5' contours were required.
An intersection or cul-de-sac detail at 0.2' contours is not out of line.
I have seen projects with 0.1' contours, mainly because the reviewing engineer could not visualize it.
Those last two were for design grades, I have no idea what grid is required to generate that from field data.
Paul in PA
Topo Grid? What's that? Isn't that the way George Washington did surveys?
This is 2016 not 1776; how much time did you waste laying out a 10 foot grid?
I've done A LOT of topo work. Every shot I take; I look around and see the shots I've taken and the shots i'm going to take. I visualize the tin lines and how they will create the contours. If you do this; systematically, will never miss a high or low spot. Ask Bruce small how he does topo...B-)
I've worked for places that wanted base lines with stationing laid out; what a waste time; I didn't stay there long...
Drag these Diehards into the Twenty-First Century; they'll thank you for it later.
I've done tight grids for ADA areas (shots as close as 3'-5') and wide open grids for big, open, flat fields (less than 2' of relief total across the site).
When we get a request from a client for an X' grid, we don't precisely layout that grid and then take shots right at each grid point. It is generally a "pace and shoot" system. High points, low points, breaklines, swales, and so on are (obviously) tied in. I build a 3D surface model and generate my contours from that. For displaying the existing elevations, I have "smart tags" in Civil3D that read the surface wherever I place them and display that elevation. I can display a 1' grid if they want.
The thing I'm working on now is training my field crews to be smarter in how they tie in the points. Part of being able to build a reliable surface is having reliable initial data. So I'm working on getting the crews better able to understand how surfaces and contours are created so that their field shots are a better representation of the ground.
skwyd, post: 366220, member: 6874 wrote: I've done tight grids for ADA areas (shots as close as 3'-5') and wide open grids for big, open, flat fields (less than 2' of relief total across the site).
When we get a request from a client for an X' grid, we don't precisely layout that grid and then take shots right at each grid point. It is generally a "pace and shoot" system. High points, low points, breaklines, swales, and so on are (obviously) tied in. I build a 3D surface model and generate my contours from that. For displaying the existing elevations, I have "smart tags" in Civil3D that read the surface wherever I place them and display that elevation. I can display a 1' grid if they want.
The thing I'm working on now is training my field crews to be smarter in how they tie in the points. Part of being able to build a reliable surface is having reliable initial data. So I'm working on getting the crews better able to understand how surfaces and contours are created so that their field shots are a better representation of the ground.
Same here. I do pace and shoot. Actually if it's an existing parking lot I use the parking stalls as a reference for where to take spot shots. They're 9' wide generally, so that's my 10' grid.
RADAR, post: 366215, member: 413 wrote: Topo Grid? What's that? Isn't that the way George Washington did surveys?
This is 2016 not 1776; how much time did you waste laying out a 10 foot grid?
I've done A LOT of topo work. Every shot I take; I look around and see the shots I've taken and the shots i'm going to take. I visualize the tin lines and how they will create the contours. If you do this; systematically, will never miss a high or low spot. Ask Bruce small how he does topo...B-)
I've worked for places that wanted base lines with stationing laid out; what a waste time; I didn't stay there long...
Drag these Diehards into the Twenty-First Century; they'll thank you for it later.
[USER=413]@RADAR[/USER], I didn't waste any time. I found a line of the boundary that I liked and I staked to that line just moving 10' further away each line. The other RPLS did the same thing from the South end and we met in the middle with no problems.
I do remember laying out grids and I can remember thinking they sucked when I was 15. This was just walking and looking at the data collector. Three steps and a shot.
Just did one two months ago for an ADA project on an existing site with buckled sidewalks and curbs, and ratty pavement. Not on a grid, but a lot of shots and many just 5 feet apart. It was a big site, lots of cars and people, and it took forever. They had to have it, and it was good money.
How Bruce does it, efficiently. Taking shots on the grid is easy since the Leica display shows the coordinates. I just watch the display and walk to the next point. Every now and then I look at the visual display of all the shots to make sure I haven't skipped a row. Sounds easy, but usually the place is thick with Texas broom and mesquite, which is why I go home covered in dust and blood. I do the grid first so I'll know later where to take the break lines. If I come across a dip or rise, then I change the NG code to X1 and just take a bunch of shots which are plotted on a separate layer I can turn off. Note that with an efficient method I don't need to spray paint every stupid dot to tell where I have been. Geez.
Current project, with a 25' grid for a new parking lot. The purple shots are grid, and the tiny green shots are the extra X1 shots. I've done some of the break lines, which are in black.
Two words for the ADA surveys, Laser Scanner.
I guess there are people who didn't read my initial thesis, which was that I thought a 10' grid was ludicirous. I also think that shooting break lines only is ludicrous. Just because the computer "CAN" interpolate that far, doesn't mean it "SHOULD" interpolate that far.
I begged the guy to not have me do a 10' grid. He insisted and I priced accordingly. Worked out for both of us.
I'm not saying that the idea of shooting what you think needs shot and making the 10' grid is wrong (well kinda), what I am saying is that I was under contract to provide a boundary and topographic survey that Included a 10' grid per their specs. I don't ever want to get caught in a trap where I provide the "10' grid" and I only had a 35' grid or something else. It was insane, but I wanted to know what everyone else was hearing.
[USER=1201]@Bruce Small[/USER] , jobs like that are much easier since you're mapping so much stuff that it works out. Typically, on projects like that, I need very few filler shots after the mapping is over. I look at it as an as-built with some topo as opposed to a topo with an as-built also. No need to be inefficient.
