plotting artefacts

[michaelchin]

Here are two examples of plotting artefacts.

One has a subduction zone with dual polarities – which does not happen on GPlates export, or in GPlates, or using GMT for plotting.

Another is some sort of artefact relating to the edge of the map, and this one happens a lot, in many of the snapshots.

This is using the Muller et al. (2019) model files, and Lauren will send you the gplately workflow she used to make the plots.

[michaelchin]

Investigation is in process. Set to "medium" priority. Let me know if "high" priority is needed.

[michaelchin]

Maybe we should split this Issue into two? It seems to me containing two separate bugs. Any idea?

[michaelchin]

This comment is from Nicky.

Not sure you want this in the issue or here, but a couple more things I’ve noticed in these images (and the notebook from the Hu model) in case they are of use. My annotations are in pink.

There are some extra grey lines that look confusing. Are these meant to be plate boundaries (or are they from velocities, everything is a similar grey to me)? E.g. two lines (corresponding to where the transform separating these plates is) between Vancouver and Farallon plates at 52 Ma. Another weird grey line at 59 Ma near the Pacific/Kula/Farallon triple junction. In what I assume is the Hu2022 model (see screenshot), a bunch of straight grey lines around the Kula/Farallon/NAM plates. Or are these intentional lines?

Like I’ve pointed out before, the code to split between ridge and transform segments doesn’t always work.

E.g. At 52 Ma in the Müller 2019 model, there is a Pacific-Kula transform that is being picked up as half of a ridge segment, half a transform segment. This isn’t necessarily a plotting artefact – the plotting is probably working as intended, but the code to split between ridge and transform segments for some reason thinks half of this boundary is a ridge (it shouldn’t be though) – and this segment is fine at 59 Ma so it might be ‘flipping’ between a transform and a ridge segment in an animation?

At 59 Ma, there are a couple of MORs that have no ‘red’ segments. Not sure if some of the boundaries should be continuously ‘red’ either.

This will also affect any stats that anyone might calculate from this code, and so if people are relying on this code to calculate specifically ridge length, then everything should be very carefully sanity checked and possibly even manually fixed… In 2016 I tested a lot of values for the ‘deviation angle’ that I think this code is based on (if it’s the same as Simon’s code? It may have all changed though), and we couldn’t find a value that could perfectly separate ridges/transforms for the AREPS model.

[michaelchin]

The comments below are from Dietmar.

I would generally disregard the maps based on the Hu model, because Hu didn’t close the topologies properly.

The artefacts in the maps based on the 2019 model are the ones to worry about. Something for Michael to look into.

[michaelchin]

This comment is based on the info from Lauren.

I've uploaded the notebook here:

https://github.sydney.edu.au/EarthByte/EarthByteWorkflows/blob/pacific-maps/Maps/GPlately_orthographic_maps.ipynb

The current time range it's set to is 59-61, i.e. it only plots the 59Ma plots for demo purposes.

This will require the gplately branch update_data_download https://github.com/GPlates/gplately/tree/update-data-download/gplately to be used instead of main gplately because this branch has Hu2022 on the DataServer.

[michaelchin]

Hi @cpalfonso,

if you need to finish subduction teeth related work, maybe you can look into the "subduction zone with dual polarities" problem as well? Maybe we should create a new Issue for the "subduction zone with dual polarities" problem because this Issue seems containing multiple problems. It is hard to track multiple problems in one Issue.

[michaelchin]

This Issue contains information about multiple potential problems. The triage is still in progress. I am trying to break this Issue into small and actionable Issues. Please be patient with us. Thanks.

[michaelchin]

The triage is complete. This Issue has been divided into three new Issues #188 #191 #193. We will tracking the progress of fixes in the new Issues.

I will close this Issue in 7 days to leave some time for comments, objections and debates regarding various aspects of this Issue.

[michaelchin]

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