Breaklines

*Blinks*

No breaklines?

Tell them they're idiots.

:good: breaklines are the backbone of an accurate tin.

Breaklines propery used create the most accurate surface.
Some firms allow the office tech to place breaklines. Years ago using the old Wildesoft data processing, you could collect graphic lines and breaklines in separate files in the field. I have not seen another system use such a technique.
If breaklines are collected and used properly modeling is much easier and accurate.
I have done models for highway construction that were miles long with thousands of points and without using breaklines I could never be certain of the accuracy of my work.
Amazingly some firms have techs doing breaklines without seeing the site!

Say what cornbread???

weird! i suppose mathematically, if the crew collects data on a super tight grid, there would be no difference, but that is crazy talk.

I agree. I would shoot them, but they wanted no break line code. Just call it a dirt shot. I wanted to at least call them breaks even if they weren't going to use them in the tin, to alert the drafter of the feature. That wasn't acceptable. Also I never saw final product, was only consulted if there were issues on buildings or utilities.

They are the only firm that ever used these policies. Break lines have always been stressed to me as a key to a good topo.

Foolish.
Not only should the CAD operator use breaklines, but the field crew needs to be educated on how a TIN works and how to take shoots along breaklines.

Scott

even with a super tight grid the tin will fail to show the breaklines

on the converse, i worked with a fellow who would only use breaklines and would not revise the tin where it obviously needed some attention. engineering tech. lazidiot.

I know how tins work. Believe me I brought the subject up on several topos. Even offered to sit down with the drafter a work him through creating them. They had no interest. Basically told me it worked this long, why change now. It seemed learning to use them was too much trouble. The Drafter had been drafting over 30 years and was very good at flipping triangles, but Break Lines would have improved the product.

That's just stoopid...

no matter how tight the topo shots are, the tin won't be correct without the proper breaklines, especially once cross-sections are cut from the tin. for instance, full street + curb and gutter x-sections: without a top/face curb line, the tin will connect from your flowline gutter shot to the top/back curb shot. our typical urban street cross sections include the crown of the pavement, pavement shots taken to locate striping linework, edge of pavement/lip of gutter, flowline gutter, top/face curb, top/back curb, back of sidewalk, natural ground shots as needed out to the r/w and perhaps past the r/w if so required. we create linestrings in our descriptors for anything that will help create the tin and/or the basemapping. linestrings are created for lip/gutter, top/face curb, top/back curb, back/sidewalk, fencing, etc. the more info you bring into CAD, the better the mapping will be.

I worked with a similar, any time the ground made a slight/imperceptible grade change, BREAKLINE! I used breaklines topoing a friggen cornfield. Oh my it seems these little gems are misunderstood by some.

I don't have the file anymore, but while in school we did a topo of our campus; in one area the contours were horrible and didn't show that it was a berm for a drain field (of sorts). I added the breaklines and it became a radically different animal.

yes, I meant in crazy theoretical sense, sort of like laser scanning but with manual shots. 😉

oh wait, i think the routine would work if you took a crazy density of shots on the breaklines, then a normal number of shots for plain jane topo shots.

I remember the last job I did without breaklines. It took almost as much time to get the map to look right as it did to shoot the points. That was in about 2000. Now, most topo surveys we do (many of which are lengthy route surveys) are almost complete after hitting F2F with coded breaklines back at the office. Very, very little manipulation of the TIN that is automatically generated. It's more accurate and more efficient by miles over the previous method of careful cross-sectioning.

:good:
Exactly

Folks who refuse to use breaklines, or don't know how to use them, well that's difficult. The way dad taught me was he made me contour by hand a small topo. Once I saw that I was trying to interpolate past a rapid change, and what it actually did, that's when I understood the breaklines and why they are so important in a normal topo. Consequently, I have taught my crews the same way. Take a piece of a topo and make them contour where you need a breakline and where not, then show them the difference. The result is always eye opening, and Christ almighty, after one time, everyone of them "gets" it and topo mapping is SOOOOO much better.

I've done some contouring with my scanner. Small scans, 50k points or so. These require NO breaklines and it would be fruitless to try, but there's an effing point every 0.3' so what the hell, right?

I always figured that the easiest way to train a rodman how to gather shots for a proper topo was to have them process the topo on the computer (after all, who knows better which shots were taken where and why?). Once they had to contour their own topo shots, they'd learn very quickly the advantages of a properly placed shot and a properly coded breakline.

JBS

All you have to do is watch what a shot on a power pole along the back of a ditch bank does to a topo when it triangulates over to the centerline and skips the flowline of the ditch and ep of the road. makes a cool little saddle where none actually exists.