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Importing an Excel point XYZ elevation file into COMSOL for modeling ice flow
Posted Feb 11, 2010, 1:35 p.m. EST Geometry, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.2 26 Replies
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I have an microsoft excel spreadsheet that has 475 point locations with known latitude, longitude surface elevation, and depth of ice for each point on a valley glacier. I also have 40 locations with known velocity vectors (for ice flow), ice temperature information, and bed condition knowledge (frozen non-slip bed).
I hope to create a 3D representation of our research site using COMSOL and the data I have obtained. My question is very simple but the answer is likely complex: What is the easiest way to import the point data set from excel into COMSOL to create a 3D solid which I can then manipulate the properties and boundary conditions of?
So far I have figured out that I can convert the point dataset to a DXF file and import the file into COMSOL but COMSOL will not read the DXF file for some reason. I can also grid the point file in ArcGIS 9.3 or Golden Software Surfer, or any other number of programs but Im not sure if this is an appropriate way to do it.
Not having a strong MATLAB programming background, is their a relatively easy way to import a surface elevation and bed topography data set, merge the two data sets in COMSOL, and create the medium between the two data sets that of ice (known temperatures, viscosity, etc.)?
The excel file has columns labeled A: Latitude B:Longitude C: Elevation D: Bed elevation
A long and complex question I know... but any help would be useful.
Thanks
Seth
Hello Seth Campbell
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i hope somebody help us....
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I have 7 excel sheets, with x,y,z coordinates, of different geological layers, to be imported into COMSOL, to set up the basic model of the reservoir. Any ideas how to import an excel sheet into COMSOL?
Appreciate your time and kindness!
regards from Berlin
I got the same cuestion, it will be nice if there is an option like that, because using arcgis to modeling someplaces, like rivers and sea shore...
i hope somebody help us....
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check the forum, for some months ago a file was posted with a short instruction how to import a geometry from a series of xyz coordinated from an external file (origine COMSOL France I believe)
--
Good luck
Ivar
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I don't find the instructions. Could you tell me exactly where to find them?
Thanks
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In my case, I imported .stl file (both ASCII or binary type) into COMSOL to build my geometry. It works perfectly!
regards
Hi,
I don't find the instructions. Could you tell me exactly where to find them?
Thanks
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I have a xyz coordinates file, Could you tell me how can import the topography in COMSOL?
Thank you
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I have xzy files, which I converted into .stl files with ParaView, and then I imported the .stl files into COMSOL.
regards
Liwah
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I downloaded Paraview, but It doesn't read my xyz file, Could you tell me how I must format the xyz file?
This is an axample of my file
474490.113 4176294.165 431.308
475490.113 4181294.165 958.246
475490.113 4180294.165 809.776
Column are separeted by tabulation.
Thank you very much
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On this page
www.comsol.com/support/knowledgebase/838/
It is told that "The new Parametric Surfaces feature in 4.2 allows for creation of surfaces based on analytical expressions or look-up table data." But I can't find the lookup-table function.
How is this done, if I have a point set consisting of (X,Y,Z)-Data?
Best regards,
Christian
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thank you very much.
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regards
Liwah
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regards
silvia
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regards
silvia
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- decrease the geometry size i.e. dimension, number of elements, number of 3D geometries in one model
- use only the default features in COMSOL i.e. instead of importing a (complicated) 3D geometry, start with a block (etc), or a 2D rectangle (etc) and extrude/revolve it into 3D
- include as least geometries and physics as possible, I mean only the important ones, to optimize the runtime of COMSOL
I had bad time running COMSOL when I build a model which is of a best scenario, it takes 2-3 days (even with a super computer or server), so I split my model into a few sub models, and COMSOL 4.0a and former work better finally.
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I don't want to reveal too much, but you can expect news in the area of Digital Elevation Model import in the upcoming version 4.2a (premiered at the COMSOL conference in Boston in October).
That's great!!!
In fact I was a little disappointed to find that COMSOL cannot import DEMs when we bought COMSOL with Earth Science module.
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I tried out the Interpolation in 4.0, it somehow works fine but I wonder how can I show all interpolated data (says I have a few interpolations for different geological layers) in one GUI? when I plot one, the others are replaced...
Finally, I got my problem solved. I followed the example rock_fracture_flow_3d_42. I used an interpolation function (with a text file giving x,y,z coordinates which defines the land surface), a block, parametric surface (using the interpolation function), then convert to solid, split and delete entities to create the geometry. Hope the example will help you all. This needs comsol 4.2.
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I hope this can help you.
1. under Global definitions > Functions> Interpolation, select Data source "file", Brows for your file, Select the sheet (Sheet1 for example), the range and then in your case, Number of arguments 2, under function name pick what you want (I like "Altitude") . This can take quite some time.
2. plot to check that everything is ok
3. under Model>Geometry> More primitives>Parametric surface
insert
name s1
min 0
max x1x2
name s2
min 0
max y1y2
under expressions set:
x: s1
y: s2
z=Altitude(s1+x1,s2+x2)
where x1 is your x_min, x2 your x_max, y1 your y_min and y2 your y_max
Axis type: Cartesian
x: 0
y:0
z:1
change the number of knots to >100 (or until you get a good enough resolution of your surface)
Build Selected
4. Create a Solid block with the dimensions of your analysis volume (Note, if you have a plateu, i.e. a flat surface, the interpolation might have some trouble, jut edit your xls file so the points are not exaclty the same), intersected by the surface
5. use Partition to separate the strata
Hope this helped!
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Hi there
I have xzy files, which I converted into .stl files with ParaView, and then I imported the .stl files into COMSOL.
regards
Liwah
Hi,
Could you tell the steps you followed in ParaView for converting the xyz file into .stl file, please?
Is it possible to convert it it from .txt / .csv / .xlsx to .stl using it?
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I am new to COMSOL and am using version 4.2.
I am trying to build a model with surface topography. I have the x, y and z coordinates in a .txt-file. When I set up the function "Interpolation" I can only draw the function if i check "use space coordinates as arguments" box. But then I get a fatal error if I try to set up the parametric function: Fatal error during assembly or evaluation.
If I do not check the space coordinate box then I cannot draw the function but do not get the fatal error when trying to build the parametric surface but also I do not get the right topography.
Does anyone know where the problem can lie? Attached is the mph file
Thanks in advance!
Attachments:
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You may want to update your license to the current version: in 5.2 your file works right out of the box, see screenshot attached.
Best,
Jeff
Attachments:
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thanks for the fast reply. We have thought about updating our license but it we do it will still take a while. Do you know where the mistake lies for the 4.2 version? Oh and as I see from your figure: The parameters s1 and s2 range from 0 to 1500 each not from 0 to 150. (In my model it does not make a difference - I still get the same errors or wrong topography). Could you maybe attach a figure with the right ranges just for me to check that with the newest version the topography gets displayed correct?
Thank you!
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Sorry, I don't have 4.2 any more.
Attached is the screenshot after I increased the ranges for s1 and s2 to 1500. You'll notice that I increased the number of knots from 10 to 100 to capture your elevation data better.
Best,
Jeff
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