# [aspect-devel] ASCII files - Cut a 2D spherical model in slices

Wolfgang Bangerth bangerth at colostate.edu
Sat Jan 20 07:55:46 PST 2018

```> I'm sorry if it was a bit unspecific :) Trying to explain better what I would
> need:
> I would like, first of all, to look (in numbers) how viscosity, velocities,
> density, temperature etc. evolves with depth in a model.

I see. In that case, you probably want to look at the 'depth average'
postprocessor that computes averages for depth slices at every time step.

> So, for example, I now have another one. I don't know if it's correct to write
> a new question within an old one, but I would like to avoid a spamming effect
> for you all! Please, tell me if it's not correct.

In general, start a new thread with a new subject. This way, people searching
for past conversations can more easily see what a given thread is about.

> The new question is: I implemented GPlates velocities as boundary conditions
> for my 2D spherical model.The slice at which my first model was cut was the
> geographic equator (the default Point one and Point two section of the
> cookbooks...). Since I would like to cut my model using different coordinates,
> I tried to change them several times (paying attention to change them to
> colatitude and longitude -in radians-), but what I got was always a cut slice
> through the geographic equator.
> I visualize it with Paraview, using the coastline file.
> What am I missing?

I don't know for sure, but this is how this sounds to me: When you do a 2d
computation, ASPECT does this in x-y coordinates that when you naively
visualize it in Paraview is embedded into a 3d coordinate system in the
equatorial plane. But that doesn't mean that the slice you are computing on
actually *is* in the equatorial plane -- it's just that the 2d slice is
embedded into the 3d coordinate system that way. You'll have to figure out a
way to embed it so that it matches the actual slice you compute on.

Best
W.

--
------------------------------------------------------------------------
Wolfgang Bangerth          email:                 bangerth at colostate.edu
www: http://www.math.colostate.edu/~bangerth/

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