Dear Everyone,
I try to simulate 3D subduction simulation and I converted the geometry using Mercator projection for my mesh geometry.
Does Pylith provide spatial database format in mercator projection (the available projection as seen in the manual is the UTM projection)?
One more question, in the example,one part of the projection’s setting using UTM:
coordsys.projector.proj_options = +lon_0=-122.6765 +lat_0=45.5231 +k=0.9996
What does “k” refer to?
Thank you in advance.
-Alvina K K
Dear Alvina,
Yes, you can use a Mercator projection for your mesh geometry. The underlying mechanism for coordinate transformations is Proj (https://proj.org). I’m not sure, but I believe that for PyLith 2.x, you need Proj 5 or earlier. You can use any projection allowed by Proj. The k is the scaling parameter (see Proj documentation).
Cheers,
Charles
Dear Charles,
Thank you for your answer. I understand now.
I have a problem when I run the simulation (3d subduction step02.cfg) and I obtained this error :
RuntimeError: Could not find final slip at ( 161105 59085.4 -25000) using spatial database Final slip.
In the beginning, I thought it was because I used the wrong projection.
But then I just try to run again the simulation after fixed the projection issue and I still obtain this error.
What do these numbers ( 161105 59085.4 -25000) refer to?
Thank you in advance.
-Alvina K K
Dear Alvina,
The numbers are the coordinates (in your projection) of the point where PyLith is trying to find the slip. You should make sure that point is contained within your spatial database.
Cheers,
Charles
Dear Charles,
There is no point with this coordinate in my spatial database.
Why does Pylith try to find this point which is not written in the spatial database as the input?
And how to fix this problem?
Thank you for assistance.
-Alvina KK
Dear Alvina,
That is a vertex in your mesh where PyLith is trying to find the slip value. That exact point may not exist in your spatial database, but you should have points surrounding the vertex, or PyLith will not be able to do the linear interpolation. It might be helpful for you to plot the fault mesh and the points in the spatial database to make sure they are in agreement.
Cheers,
Charles
Dear Charles,
I understand now. Thank you for your explanation.
Regards,
Alvina K K