Skip to main content
Solved

How to create points on a (measured) line?

T
Forum|alt.badge.img

Dear FME community,

I have created measures on a line geometry (thanks to @takashi, your tips are very helpful!). For every vertex the measures are attached to the geometry. In my attribute table, I have a column of the original measures.

For example:

A line is 1000 metres long. In the attribute table there is a column "beginning station" with the value 0, and a column "end station" with the value 800. The resulting line which I want to get should therefore be only 800m long, starting from point 0. If it would start at 400 and go to 800, the line would then only be 400m long.

I have calculated the measures, but how can I split the line on the measures I want, e.g. 800? Is there a way to create points on these locations, so that I can intersect them with the original line?

Every help is appreciated! Many thanks.

Kind regards

Thomas

Best answer by ebygomm

Have you looked at the snipper transformer? You can use the measures within this

View original
    Did this help you find an answer to your question?

    9 replies

    ebygomm
    Influencer
    Forum|alt.badge.img+38
    • ebygommInfluencer
    • Influencer
    • Best Answer
    • August 8, 2016

    Have you looked at the snipper transformer? You can use the measures within this

    T
    Forum|alt.badge.img
    • thomask
    • Author
    • August 8, 2016

    Thank you @egomm! I have just found the Snipper and from what I see it's the perfect transformer for this. I'm just not quite sure which setting would be more suitable: Measure (Relative to Start Point) or Measure (Value). My measures which I created with the MeasureGenerator were multiplied by a factor to get the appropriate length (if thats of any help).

    david_r
    Celebrity
    • david_rCelebrity
    • August 8, 2016

    If you send your line features to the Inspector you can see the measure values next to the coordinates, which I personally find very helpful when debugging LRS features. If you have applied a factor to your measures, you will of course also have to take that into account in your start and end location values (publicWFS_vst / publicWFS_bst).

    You should probably use "Measure (value)" in your case. The different modes are explained in the help.

    T
    Forum|alt.badge.img
    • thomask
    • Author
    • August 8, 2016

    Thank you @david_r! I was wondering because the number of lines was smaller in the output port of the Snipper than before. Aren't there supposed be more or at least the same number of lines in the output compared to the input, when they are "snipped"?

    david_r
    Celebrity
    • david_rCelebrity
    • August 9, 2016
    thomask wrote:

    Thank you @david_r! I was wondering because the number of lines was smaller in the output port of the Snipper than before. Aren't there supposed be more or at least the same number of lines in the output compared to the input, when they are "snipped"?

    It's difficult to tell without knowing the details of your data and your workspace. Do you by any chance have aggregate features entering the Snipper? They will not be processed and will exit the <Rejected> port.

     

     

    I would suggest isolating a single input object where this happens and sending the before and after to the Inspector for analysis.

     

    T
    Forum|alt.badge.img
    • thomask
    • Author
    • August 9, 2016
    david_r wrote:
    It's difficult to tell without knowing the details of your data and your workspace. Do you by any chance have aggregate features entering the Snipper? They will not be processed and will exit the <Rejected> port.

     

     

    I would suggest isolating a single input object where this happens and sending the before and after to the Inspector for analysis.

     

    I'm trying to figure it out with a subset of the data. In the log file it says for example:

     

    @Snip (or FMELine::snip) was given Measures of 1468 and 1974, which are out of range for a line with min/max measures of 0 and 1974. Snapping params to closest valid value.
    The first measure for this line at coordinate zero is:

     

    Coordinate 0: 333098.47953629337, 5623070.8301944714

Measures:
<default_measure> = 0.0
    And the last one:

     

    Coordinate 135: 334772.80646645062, 5624034.9839437641

Measures:
<default_measure> = 1973.9999999999952

     

    Although these are only little difference, perhaps one could round the measures, so that it fully matches with the values in the attribute? Anyone know if that's possible?

     

    david_r
    Celebrity
    • david_rCelebrity
    • August 9, 2016
    thomask wrote:
    I'm trying to figure it out with a subset of the data. In the log file it says for example:

     

    @Snip (or FMELine::snip) was given Measures of 1468 and 1974, which are out of range for a line with min/max measures of 0 and 1974. Snapping params to closest valid value.
    The first measure for this line at coordinate zero is:

     

    Coordinate 0: 333098.47953629337, 5623070.8301944714

Measures:
<default_measure> = 0.0
    And the last one:

     

    Coordinate 135: 334772.80646645062, 5624034.9839437641

Measures:
<default_measure> = 1973.9999999999952

     

    Although these are only little difference, perhaps one could round the measures, so that it fully matches with the values in the attribute? Anyone know if that's possible?

     

    Rounding errors can be a bit pesky, but it shouldn't really matter in this case. The Snipper will "snap" to the closest valid value by default. So in the example above you should get the line from 0 to 1973.9999999999952 when you ask to snip from 0 to 1974.

     

    Or do you get something else?

     

    T
    Forum|alt.badge.img
    • thomask
    • Author
    • August 9, 2016
    david_r wrote:
    Rounding errors can be a bit pesky, but it shouldn't really matter in this case. The Snipper will "snap" to the closest valid value by default. So in the example above you should get the line from 0 to 1973.9999999999952 when you ask to snip from 0 to 1974.

     

    Or do you get something else?

     

    Yes, the line goes to 1974. So the result is correct. I was just wondering because of the numerous warnings regarding this rounding thing in the log file. But I will look further into the data and report back when I find anything.

     

     

    T
    Forum|alt.badge.img
    • thomask
    • Author
    • August 26, 2016

    Hey guys, just to let you know in case someone has a similar problem: the proposed solution with the snipper transformer works perfectly. The rounding messages were just a warning, the result is correct.

    Reply


    Helpful Members This Week

    Community Stats

    31,333
    Posts
    118,863
    Replies
    38,957
    Members

    Latest FME

    Terms & ConditionsCookie settings

    Cookie policy

    We use cookies to enhance and personalize your experience. If you accept you agree to our full cookie policy. Learn more about our cookies.

     
    Cookie settings
    A product of
    Safe Software respectfully acknowledges that we live, learn and work on the traditional and unceded territories of the Kwantlen, Katzie, and Semiahmoo First Nations.