# A continent crust suddenly loses raster

**URL:** https://discourse.gplates.org/t/a-continent-crust-suddenly-loses-raster/763
**Category:** Q&A
**Created:** [1 November 2023 21:02 UTC](https://discourse.gplates.org/t/a-continent-crust-suddenly-loses-raster/763 "2023-11-01T21:02:52Z")
**Posts on this page:** 1
**Showing post:** 6

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### Author: ![john.cannon](https://discourse.gplates.org/letter_avatar_proxy/v4/letter/j/3e96dc/32.png) [@john.cannon](https://discourse.gplates.org/u/john.cannon)
#### Post date: [13 November 2023 03:35 UTC](https://discourse.gplates.org/t/a-continent-crust-suddenly-loses-raster/763/6 "2023-11-13T03:35:17Z")

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> [@TCanc](#):
>
> I tried an experiment moving the continent to the “center” so it wouldn’t wrap around the edges, but no dice.

Actually that was just an example of a polygon that would fail to render a raster (when I mentioned _“think of a thin polygon following a vertical meridian and extending past both the North and South poles”_).

GPlates is generally agnostic to the poles and the dateline (in its internal operations). So any rotation/reorientation of a problematic problem will still have the same issue in GPlates.

> [@TCanc](#):
>
> To speed up the process I exported the coordinates in a txt file and copied under here

Thanks for that. I converted that output to a GPML file using [PlateTectonicTools](https://github.com/EarthByte/PlateTectonicTools) with `python -m ptt.convert_xy_to_gplates -l -p polygon-breaks-raster.txt` (after removing the last line and adding an empty line beginning with `>` at the top). Also note that PlateTectonicTools will soon be part of [GPlately](https://github.com/GPlates/gplately).

After loading it into GPlates I can see that while it can be filled (see image below) it cannot render a raster for the reason I stated in a previous post. It exceeds the internal limit of 162 degrees (it’s actually not 180 degrees as I mentioned earlier). And your polygon spans about 170 degrees. You can measure this with the `Measure` tool on the 3D orthographic globe by clicking two points near each end of the polygon (and then read the line distance).

In a future version of GPlates I am considering an alternate approach to avoid this issue.

![image](https://discourse.gplates.org/uploads/default/original/1X/2942a5abfbbf1a913899e54ecb96aeaf5367cdd7.png)

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