[issm-support] Issues with meshing..
Larour, Eric (385J)
eric.larour at jpl.nasa.gov
Mon Dec 31 14:18:47 PST 2012
Derrick,
I ran your example and everything went fine. So the only thing right now
I can think
of is that your model is not in sync with svelint (i.e. svelint is not a
vertex based vector of
size (md.mesh.numberofvertices,1)). To check on that, could you send me
the results of the following?
>> md.mesh
>> whos x y svelocity svelint
Thanks!
Eric L.
On 12/31/12 1:53 PM, "Larour, Eric (385J)" <eric.larour at jpl.nasa.gov>
wrote:
>Derrick,
>
>I'm also puzzled as to why bang is giving you an error. I am right now
>working
>on reproducing the bug from your procedure document. Will keep you posted
>as soon
>as I find the bug. Should not be long.
>
>For further reference, please include issm-support at issm.ess.uci.edu in
>your reply
>all, so other ISSM folks can also help you :)
>
>Eric L.
>
>
>
>
>
>On 12/31/12 12:17 AM, "djl22" <djl22 at psu.edu> wrote:
>
>>Hi,
>>
>>I think I found a way through it. I tried working with the original
>>data, which provides surface velocity over the entire Greenland ice
>>sheet projected in polar stereographic. I used geotiffread to import the
>>GEOTIFF image. I used exptool to draw my domain as a sub-region
>>(Jakobshavn area) from the imported image and set the initial resolution
>>of my mesh at 2km (2000m). The output mesh looks about right. I then
>>extract the pixel center coordinates using the pixcenters command:
>> >>info=geotiffinfo(filename);From
>> >> [x,y] = pixcenters(info);
>>
>>This gets my coordinates for pixel centers. I then have to flip my (y)
>>coordinates because the InterpFromGridToMesh command complains that the
>>values should be decreasing. After doing so I run the
>>InterpFromGridToMesh command and here things get odd. I notice that in
>>your examples the velx and vely variables in your Searise and jakobshavn
>>examples are entered in the InterpFromGridToMesh command as the
>>transpose of these variables, is this correct? (i.e.
>>vx=InterpFromGridToMesh(x1,y1,velx',md.mesh.x,md.mesh.y,0);).
>>If I enter my velocity grid as such then I get an error. if I enter
>>without the transpose the command seems to work, but then I get an odd
>>message when I use the output from the Interp command in the following
>>bamg command. I get:
>>
>>Anisotropic mesh adaptation
>>Error message: 'field' should have 930 rowsError using BamgMesher
>>
>>At this point I'm lost as to why its not working. When I attempted to
>>run your Searise example as indicated, I ended up with the same exact
>>error in running bamg (I ran the lines of code provided directly from
>>the example). I also go tthis error when I ran the Searise example:
>>Error message: Input parameter of class single not supported yetError
>>using InterpFromGridToMesh
>>
>> when I ran
>>vx=InterpFromGridToMesh(x1,y1,velx',md.mesh.x,md.mesh.y,0);...in this
>>case I converted the input variables x1, y1 and velx, vely to double
>>(x1=double(x1), etc...) was this necessary to get it to work? The
>>command worked after doing this which means ISSM could not recognize the
>>data type "single" as oppose to "double"
>>
>>at any rate, i'm now stuck at bamg where I'm attempting to use the
>>velocity i assume were interpolated to my initial mesh within my custom
>>domain to refine my initial mesh which would ideally create finer mesh
>>grids near the margins of Jakobshavn than outside of the margins....
>>
>>Thanks so much for the assistance....
>>
>>
>>On 12/29/2012 3:04 AM, Larour, Eric (385J) wrote:
>>> Dear Derrick,
>>>
>>> I think the issue is that when you plotted your surface velocities in
>>> matlab (before calling exptool
>>> on it), you did not specify the x and y coordinates of your image.
>>>
>>> Typically, in matlab, one does:
>>>
>>> imagesc(velocity) where velocity is a matrix. This will get you
>>> coordinates in scene coordinates.
>>>
>>> For your example, what you need to do is:
>>> imagesc(x,y,velocity),
>>> where x=0:(xmax-xmin)/m:xmax and
>>> y=0:(ymax-ymin)/n:ymax
>>>
>>> and m,n is the size of the velocity matrix.
>>>
>>> If you do this, you will recover from exptools the true vertex
>>> coordinates.
>>>
>>> Tell me how it goes!
>>>
>>> Thanks!
>>> Eric L.
>>>
>>>
>>>
>>> On 12/28/12 11:58 PM, "Derrick Lampkin" <djl22 at psu.edu> wrote:
>>>
>>>> Greetings,
>>>>
>>>> I recently attended the ISSM workshop and found it useful. I'm
>>>>attempting
>>>> to use the system to model a system in the Jakobshavn outlet basin. I
>>>> have been using your Jakobshavn example as a template. The exception
>>>>is
>>>> I'm using a base of surface velocity data derived from NSIDC (Joughin
>>>> data set). I have imported a surface velocity grid as GEOTIFF into
>>>>matlab
>>>> and I use the exptool to draw the outline of my domain on top of this
>>>> base map. The map is in the polar stereo graphic projection but when I
>>>> create the initial mesh using triangle at the nominal resolution of
>>>>the
>>>> data (500 m), the grid spacing was not nearly as dense as expected. I
>>>> inspected the domain file I created and the vertices coordinates are
>>>>in
>>>> scene coordinates (row/column) values and not the projected
>>>>coordinates ,
>>>> therefore the mesh spacing are not reasonable and do not correspond to
>>>> the specified resolution I indicate in the triangle command. How might
>>>>I
>>>> fix this issue?
>>>>
>>>> Thanks
>>>>
>>>> derrick j lampkin
>>>> __________________
>>>> research professor
>>>>
>>>> institute of arctic and alpine research
>>>>
>>>> university of colorado-boulder
>>>>
>>>> __________________
>>>>
>>>> email: djl22 at psu.edu
>>>>
>>>> _______________________________________________
>>>> issm-support mailing list
>>>> issm-support at issm.ess.uci.edu
>>>> http://issm.ess.uci.edu/cgi-bin/mailman/listinfo/issm-support
>>
>>
>>--
>>derrick j lampkin
>>__________________
>>research professor
>>
>> institute of arctic and alpine research
>> university of colorado-boulder
>>adjunct
>> department of geoscience
>> pennsylvania state university
>> __________________
>>
>>email: djl22 at psu.edu
>>web: http://www.geosc.psu.edu/academic-faculty/lampkin-derrick
>>
>
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