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Hi Derrick,
<div><br>
</div>
<div>it sounds like the problem is coming from the output of InterpFromGridToMesh, not from bamg.</div>
<div>bamg complains because the field that is provided (the ice velocity) does not have the right size.</div>
<div>The vector 'field' that is used by bamg should be of length [md.mesh.numberofvertices 1].</div>
<div><br>
</div>
<div>You should check that when you do</div>
<div>vx=InterpFromGridToMesh(x1,y1,velx',md.mesh.x,md.mesh.y,0);</div>
<div><br>
</div>
<div>size(vx,1) == md.mesh.numberofvertices;</div>
<div><br>
</div>
<div>you can also "plot" vx to check that it looks ok:</div>
<div>plotmodel(md,'data',vx);</div>
<div><br>
</div>
<div>let us know if it helps.</div>
<div>
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<div>--</div>
<div>Mathieu Morlighem</div>
<div><br>
</div>
</div>
</div>
<br>
<div>
<div>On Dec 31, 2012, at 10:53 PM, "Larour, Eric (385J)" <<a href="mailto:eric.larour@jpl.nasa.gov">eric.larour@jpl.nasa.gov</a>> wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">Derrick, <br>
<br>
I'm also puzzled as to why bang is giving you an error. I am right now<br>
working <br>
on reproducing the bug from your procedure document. Will keep you posted<br>
as soon<br>
as I find the bug. Should not be long.<br>
<br>
For further reference, please include <a href="mailto:issm-support@issm.ess.uci.edu">
issm-support@issm.ess.uci.edu</a> in<br>
your reply <br>
all, so other ISSM folks can also help you :)<br>
<br>
Eric L. <br>
<br>
<br>
<br>
<br>
<br>
On 12/31/12 12:17 AM, "djl22" <<a href="mailto:djl22@psu.edu">djl22@psu.edu</a>> wrote:<br>
<br>
<blockquote type="cite">Hi,<br>
<br>
I think I found a way through it. I tried working with the original<br>
data, which provides surface velocity over the entire Greenland ice<br>
sheet projected in polar stereographic. I used geotiffread to import the<br>
GEOTIFF image. I used exptool to draw my domain as a sub-region<br>
(Jakobshavn area) from the imported image and set the initial resolution<br>
of my mesh at 2km (2000m). The output mesh looks about right. I then<br>
extract the pixel center coordinates using the pixcenters command:<br>
<blockquote type="cite">
<blockquote type="cite">info=geotiffinfo(filename);From<br>
[x,y] = pixcenters(info);<br>
</blockquote>
</blockquote>
<br>
This gets my coordinates for pixel centers. I then have to flip my (y)<br>
coordinates because the InterpFromGridToMesh command complains that the<br>
values should be decreasing. After doing so I run the<br>
InterpFromGridToMesh command and here things get odd. I notice that in<br>
your examples the velx and vely variables in your Searise and jakobshavn<br>
examples are entered in the InterpFromGridToMesh command as the<br>
transpose of these variables, is this correct? (i.e.<br>
vx=InterpFromGridToMesh(x1,y1,velx',md.mesh.x,md.mesh.y,0);).<br>
If I enter my velocity grid as such then I get an error. if I enter<br>
without the transpose the command seems to work, but then I get an odd<br>
message when I use the output from the Interp command in the following<br>
bamg command. I get:<br>
<br>
Anisotropic mesh adaptation<br>
Error message: 'field' should have 930 rowsError using BamgMesher<br>
<br>
At this point I'm lost as to why its not working. When I attempted to<br>
run your Searise example as indicated, I ended up with the same exact<br>
error in running bamg (I ran the lines of code provided directly from<br>
the example). I also go tthis error when I ran the Searise example:<br>
Error message: Input parameter of class single not supported yetError<br>
using InterpFromGridToMesh<br>
<br>
when I ran <br>
vx=InterpFromGridToMesh(x1,y1,velx',md.mesh.x,md.mesh.y,0);...in this<br>
case I converted the input variables x1, y1 and velx, vely to double<br>
(x1=double(x1), etc...) was this necessary to get it to work? The<br>
command worked after doing this which means ISSM could not recognize the<br>
data type "single" as oppose to "double"<br>
<br>
at any rate, i'm now stuck at bamg where I'm attempting to use the<br>
velocity i assume were interpolated to my initial mesh within my custom<br>
domain to refine my initial mesh which would ideally create finer mesh<br>
grids near the margins of Jakobshavn than outside of the margins....<br>
<br>
Thanks so much for the assistance....<br>
<br>
<br>
On 12/29/2012 3:04 AM, Larour, Eric (385J) wrote:<br>
<blockquote type="cite">Dear Derrick,<br>
<br>
I think the issue is that when you plotted your surface velocities in<br>
matlab (before calling exptool<br>
on it), you did not specify the x and y coordinates of your image.<br>
<br>
Typically, in matlab, one does:<br>
<br>
imagesc(velocity) where velocity is a matrix. This will get you<br>
coordinates in scene coordinates.<br>
<br>
For your example, what you need to do is:<br>
imagesc(x,y,velocity),<br>
where x=0:(xmax-xmin)/m:xmax and<br>
y=0:(ymax-ymin)/n:ymax<br>
<br>
and m,n is the size of the velocity matrix.<br>
<br>
If you do this, you will recover from exptools the true vertex<br>
coordinates.<br>
<br>
Tell me how it goes!<br>
<br>
Thanks!<br>
Eric L.<br>
<br>
<br>
<br>
On 12/28/12 11:58 PM, "Derrick Lampkin" <<a href="mailto:djl22@psu.edu">djl22@psu.edu</a>> wrote:<br>
<br>
<blockquote type="cite">Greetings,<br>
<br>
I recently attended the ISSM workshop and found it useful. I'm<br>
attempting<br>
to use the system to model a system in the Jakobshavn outlet basin. I<br>
have been using your Jakobshavn example as a template. The exception is<br>
I'm using a base of surface velocity data derived from NSIDC (Joughin<br>
data set). I have imported a surface velocity grid as GEOTIFF into<br>
matlab<br>
and I use the exptool to draw the outline of my domain on top of this<br>
base map. The map is in the polar stereo graphic projection but when I<br>
create the initial mesh using triangle at the nominal resolution of the<br>
data (500 m), the grid spacing was not nearly as dense as expected. I<br>
inspected the domain file I created and the vertices coordinates are in<br>
scene coordinates (row/column) values and not the projected<br>
coordinates ,<br>
therefore the mesh spacing are not reasonable and do not correspond to<br>
the specified resolution I indicate in the triangle command. How might<br>
I<br>
fix this issue?<br>
<br>
Thanks<br>
<br>
derrick j lampkin<br>
__________________<br>
research professor<br>
<br>
institute of arctic and alpine research<br>
<br>
university of colorado-boulder<br>
<br>
__________________<br>
<br>
email: <a href="mailto:djl22@psu.edu">djl22@psu.edu</a><br>
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</blockquote>
</blockquote>
<br>
<br>
-- <br>
derrick j lampkin<br>
__________________<br>
research professor<br>
<br>
institute of arctic and alpine research<br>
university of colorado-boulder<br>
adjunct<br>
department of geoscience<br>
pennsylvania state university<br>
__________________<br>
<br>
email: <a href="mailto:djl22@psu.edu">djl22@psu.edu</a><br>
web: <a href="http://www.geosc.psu.edu/academic-faculty/lampkin-derrick">http://www.geosc.psu.edu/academic-faculty/lampkin-derrick</a><br>
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