[IDV #SME-839174]: Resolution loss viewing GINI

Hi Art-

> >> I'm viewing GINI 1km visible imagery via IDV 2.3 on Windows XP and notice
> >> that on close-up views, the imagery gets blocky and doesn't appear to be
> >> displaying at 1km resolution.  The "Displays" tab says pixel sampling is
> >> "0".  Is there some other setting I need to change to get the visible
> >> imagery to display at full resolution?
> >
> > I'm assuming you are using the Image Chooser to select the data from
> > one of the ADDE servers.  In that chooser, there are defaults set
> > for particular images and by default, since the 1km imagery is large
> > (5120x5120), there is an default blowdown of the data coming from
> > the server.  If you look at the chooser, the magnification is
> > set to -6 by default.  You can use the sliders to change this to
> > 1 for full resolution, but I would suggest you use a combination of
> > the image size and location to subset the full resolution image.
> > You can use the lat/lon or lin/ele centering with the image size
> > to zoom in over a particular area.
> 
> Okay... but I must be missing something.  I see that I can set the
> "magnification" to 1, and the location center, but where do I select the
> subset?  Is it possible to select a subset of the 5120x5120 image in full
> resolution?

You would set the lines and elements boxes.  For example, my setup
for the GINI 1km has:

mag=1
lines/elements=800 800
place=center
latlon=40 -105

If you always want this to be the default, you can create an
imagedefaults.xml file in your ~/home/.metapps/DefaultIdv directory
that would look like:

<?xml version="1.0" encoding="UTF-8"?>
<imagedefaults>
  <default
     name="GINIEAST/GE1KVIS"
     key="LATLON"
     place="CENTER"
     loc="40 -105"
     mag="1 1"
     size="800 800"/>
</imagedefaults>

We don't yet have a way for users to set these options from the
widget, but that's in the plans for some future release.  You can find
more information on the imagedefaults file in the User's Guide:

http://www.unidata.ucar.edu/software/IDV/docs/userguide/misc/ImageDefaults.html

> I also have a follow-up question:  The image displays don't seem to have
> full resolution in pixel Z-depth, i.e. the shades of
> temperature/brightness seem to jump coarsely from one level to the next
> compared to what I get when I view the same imagery in garp.  Do you know
> what would cause this and is there a setting I can change to fix that?

What's the color depth of your display (8,24 or 32?)  Garp grabs the
colors it needs right up front and the IDV uses whatever colors  are
available (left).  

Don


Ticket Details
===================
Ticket ID: SME-839174
Department: Support IDV
Priority: Normal
Status: Open