I'm creating a collection of line features from a GPX file. I've processed the points from the file to calculate things like slope and speed at the various locations. I've then generalized these slope attributes into Uphill, Downhill, and Flat. I want to use these as Connection Break Attributes to segment the LineBuilder output. However, upon doing this I've realized that there are distinct gaps in the track as there is no line connection between the vertices that start/end a line that has a different Connection Break Attribute. Is there a tidy way to attach these together?
Solved
Create continuous line builder output with connection break attributes
Best answer by takashi
Hi @warren156, how did you calculate the values of slope?
Slope is a property of 3D linear geometry, and I guess that you have calculated it based on elevations of consecutive two points.
If so, I think you can also create line segments connecting between every pair of consecutive two points and add the attribute "shape_class" (Uphill, Flat, Downhill) to the line segments, rather than to the points. You can then get desired result by connecting the line segments with the LineCombiner (called LineJoiner in older versions) grouping by the "shape_class".
This post is closed to further activity.
It may be an old question, an answered question, an implemented idea, or a notification-only post.
Please check post dates before relying on any information in a question or answer.
For follow-up or related questions, please post a new question or idea.
If there is a genuine update to be made, please contact us and request that the post is reopened.
It may be an old question, an answered question, an implemented idea, or a notification-only post.
Please check post dates before relying on any information in a question or answer.
For follow-up or related questions, please post a new question or idea.
If there is a genuine update to be made, please contact us and request that the post is reopened.
I forgot to include an image detailing what the output lines and attributes look like. I've attached it below.
+40- Contributor
The easiest thing to do would be on your original points, clone the point where the break value switches, and give the cloned point the new value (leaving the original point as is)
A: Up
B: Up
C: Flat
D: Flat
E: Down
Would become
A: Up
B: Up
B: Flat
C: Flat
D: Flat
D: Down
E: Down
This can be accomplished with an attributeCreator with Enable Adjacent Features and a Cloner.
- Best Answer
Hi @warren156, how did you calculate the values of slope?
Slope is a property of 3D linear geometry, and I guess that you have calculated it based on elevations of consecutive two points.
If so, I think you can also create line segments connecting between every pair of consecutive two points and add the attribute "shape_class" (Uphill, Flat, Downhill) to the line segments, rather than to the points. You can then get desired result by connecting the line segments with the LineCombiner (called LineJoiner in older versions) grouping by the "shape_class".
Hi @warren156, how did you calculate the values of slope?
Slope is a property of 3D linear geometry, and I guess that you have calculated it based on elevations of consecutive two points.
If so, I think you can also create line segments connecting between every pair of consecutive two points and add the attribute "shape_class" (Uphill, Flat, Downhill) to the line segments, rather than to the points. You can then get desired result by connecting the line segments with the LineCombiner (called LineJoiner in older versions) grouping by the "shape_class".
I calculated slope using the elevations between 2 points as you mentioned. However, my methodology was slightly more complicated. THe overview is that some of my GPX points are very dense (<1m apart) and other much more reasonablly space at ~100m. Therefore I buffered every GPS point by 150m (just to be safe) and overlaid that buffer on the GPS points to create a list of the eligible pointsto use for elevation sampling. I then filtered that list and kept those that were within 5 objectids on either side (this eliminated those points that were part of that GPS track that passed along the same road segment at a different point in time). These points became the extent points from which I sampled slope.
If I have it correct, I think I'm going to use the Attribute Creator with Adjacent Features and create a pair of coordinate attributes on each point and populate it with the coordinates of the Subsequent track point. I'll then create a vertex for the "root" point and the subsequent point to create line features from that geometry. I should then be able to do as you mentioned and clean everything up with the LineCombiner. (Bit of a combination of your suggestion and @jdh, I'll report back when I've completed.