Ryan,
The first thing to try is to return to the AVISO LAS site and create
your shaded plot again, but use the "Output Options" link and set the
"Interpolate data" option to "No".
If that doesn't resolve the differences, then send us the information
we need (data set and variable names) to try some experiments ourselves
on the AVISO site (those of us not familiar with the data collection
can't figure out which data set and variable you plotted from the
images).
Roland
Tony Jolibois wrote:
Dear Ryan,
I'm not familiar with the gridded output option of the LAS and GIS.
Maybe it is a problem of cartographic projection made by Ferret (the
visualisation tool used in LAS).
Maybe when you download the data from LAS an image, the data is
projected (default projection of the LAS, I don't remember which one),
and if you didn't inverse the projection maybe it can cause this type
of problem.
I cc the las user list and experts, who can respond if they have time.
Best regards,
Tony Jolibois
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Tony Jolibois
CLS, Direction Océanographie Spatiale
Département Produits et Services
8-10 rue Hermes,
31526 Ramonville-St-Agne, Cedex, France
Email: tjolibois@cls.fr
Tel: (+33) (0) 561 394 797
Fax: (+33) (0) 561 393 782
http://www.cls.fr
http://las.mersea.eu.org
http://bulletin.mersea.eu.org
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
X-Sieve: CMU Sieve 2.2
From: "Ryan Coatta" <coatta@zoology.ubc.ca>
To: <aviso@cls.fr>
Subject: AVISO Live Access Server Data Problem
Date: Tue, 14 Jun 2005 12:09:13 -0700
Organization: Marine Mammal Research Unit
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Hello - We are experiencing a
problem
with the data produced by the AVISO Live Access Server.
Both of the images below were generated using the Live Access Server
for
31-Dec-03, and have been zoomed in to Alaskan state waters for this
example. The first image was based on data obtained using the
ArcVIEW Gridded output option. The data were imported & visualized
in
ArcGIS. The second image was generated by the Live Access Server itself
using the Shaded Plot output option. Both images were produced
using the same bounding extents (170E, 115W, 30N, 65N).
The problem is that the two images are not aligned. The problem is
evident from the features circled in the upper ArcGIS image. When
comparing the two images you can see that the location of the SSH
anomaly
features do not agree from one image to the next. The difference
appears to become more significant as you move south, implying that the
error is changing with location, and therefore cannot be attributed to
a
simple shift in the data. Note that the bounding extents of the data
are
correct, implying that the correct x/y scaling factors have been
applied.
Are you familiar with this problem, and/or can you offer any
suggestions
as to how we should proceed?
Regards,
Ryan Coatta
[... images deleted... ]
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