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Home - General / All posts - Subtracting Lines from other Lines
75 post(s)
#30-Jul-18 09:06

Good day everyone!

I need some help in M8..

How do i subtract a line drawing from the other line drawing which is intersecting or touches with each other?

I have a map file here, i want to subtract Line 2 from Line 1 or the other way around. (attach unsuccessful)

Thank you in advance

288 post(s)
#30-Jul-18 09:10

(attach unsuccessful)

Try with simple filename, without spaces etc.


8,579 post(s)
#30-Jul-18 09:19

It will take a lot of luck, or a lot of time, or a lot of skill, or money. Or all four things.

Lines are very thin. They can only exclude each other exactly.

It's almost always better to go back to the source and find out how the problem arose. Then redo the work.


8,402 post(s)
#01-Aug-18 15:03

Like Tim, I don't think this is very robust. I'd do small buffers and clip using those.


3,103 post(s)
#01-Aug-18 15:32

when you say subtract, do you mean you want to delete the offending line, or do you want to clip away only that part that is offending?

If you want to get rid of the line, then a simple query like this would suffice:


FROM a, b

WHERE touches(a.[ID],

I tested it, and that of course finds the lines that are actually touching one another. But, I also created two lines that are within 3m of one another. If you change the precision to 5m, then you won't have to do any kind of buffering, as it will select those lines since they are within the tolerance.

Is that what you are looking to do? Or, do you need to clip out the part of the line that is coincident with the other line?

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