2 issues with deforming networks


For the reconstruction I am building I would like to use deforming polygons. However, I’ve been encountering two problems recently:

  1. When I build a topological network, I have individual segments of a graben that have the same feature ID. The problem that was pointed out earlier (Which features are chosen by topologies) that when features with identical IDs are added to a topological network, GPlates will use neither. However, as these are individual segments, I cannot use the scissors tool to cut split them into individual features (and this also does not seem to be possible in e.g. QGIS: GitHub - veltman/split-multipart-features: A script for selectively splitting up multipart features in QGIS.). Also, some of the features with the same feature ID are duplicates of each other, with different plate IDs (and I need to keep both). Can I simply give them another feature ID?
    Also, the topological network also seems to ignore segments that, as far as I can tell, do seem to have individual feature IDs (they also have individual plate IDs, but they were constructed by cutting up a line into different segments). Is there an easy way to solve this issue?

  2. On some occasions, when a boundary section crosses into the network back in time (because of e.g. extension), the internal deforming mesh seems to treat it as an interior segment instead. Since I’ve only encountered this a few times this might also represent a bug, but I’m not sure.

Many thanks!


Hi Thomas,

Yes, as you say, each feature must have a different feature ID - a fundamental invariant - like if you clone a sheep then the clone gets a new social security number :wink:

Yes that should work. One way to do this is to use pyGPlates to clone the feature as mentioned in the post you linked (the cloned feature is identical except for the feature ID).

If they have different feature IDs then it should work. Could be a bug - so feel free to send me your data that reproduces the problem.

Do you mean the interior segment is no longer part of the boundary? Maybe you can post a screenshot to show this. Might be some weird self-intersecting of the resolved boundary that makes it look like it’s not part of the exterior.

Hi John,

Thanks for your fast reply! By cloning the sheep the social security administration finds all of them - solving the first problem. When doing that I did not encounter the second problem anymore either. If I do, I will let you know.

Many thanks,