Saving subduction zone polarity attribute in shapefile

Q&A
1

Hi,

For my reconstruction I am building closing plate polygons. I have a .shp with a set of polylines that define a subduction zone. I want to indicate the polarity of said subduction using the gpml:SubductionZonePolarity attribute. However, when I save the shapefile and restart GPlates, the file has lost the attribute “gpml:SubductionZonePolarity”. However, I can save this information when I save it as a .gpml file.

Q: Is it in general not possible to assign attributes such as subduction polarity to a .shp file? Are there any other attributes of other plate boundaries (i.e. transforms and mid-ocean ridges) that I should be aware of that are not saved in a .shp file?

Many thanks,
Thomas

2

For topological closed plate boundaries/networks it’s best to use the native GPML format when possible (which records the complete set of feature properties).

The attributes stored in Shapefiles are listed here. These only include the most common feature properties such as time period, name/description, plate ID (and optional conjugate). And for half-stage spreading of mid-ocean ridges there’s left/right plate IDs and spreading asymmetry. But yeah, subduction polarity is not included in that.

There is work planned, for a future GPlates release, to bring Shapefiles (and other non-native file formats) more in line with the GPlates Geological Information Model.

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