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[IDV #LUU-266374]: Problems with inversion of Z axis

Hi Nick-

Since you didn't repost your message to the idvusers list, I
took the liberty of putting into our support system so I could
answer it.

> I'm using IDV to view 3D gridded ocean temperatures from here;
> 
> http://www.marine.csiro.au/dods/nph-dods/dods-data/bl/SPINUP4/temp/
> 
> The data above is encoded so that ocean depth (the z axis) is expressed
> as a positive.  I attach 2 images and ask below how we may change it's
> representation in plots and charts.
> 
> [ZAxisInversion1.jpg]
> Notice 2 problems with this; although the volume render is correctly
> drawn underneath the basemap, the cube/ROI is drawn above.  A vertical
> probe (the red line) through that same volume render data has also been
> incorrectly drawn above the basemap.

The IDV does not autoscale the Z axis to the data at this point. You
can manually change the vertical scale using the View->Viewpoint->Vertical
Range menu or by clicking on the little scale (comb) icon in the
Viewpoint toolbar.  The default is 0 to 16 km.  You could set yours
to fit your data by making the min negative.

By default, the map is placed at the bottom of the box.  You can move
it anywhere in the box using the slider in the Display tab of the
Map DisplayControl.

> [ZAxisInversion2.jpg]
> This is a chart for the probe shown above.  We can find no way to make
> the Y axis on this chart invert so that depth=0 is at top and depth=300
> is at the bottom.  Is there any IDV power user here that can offer a
> suggestion?

This is a bug and is fixed in the nightly build at:

http://www.unidata.ucar.edu/software/idv/release/nightly

Thanks for finding this.  I wasn't accounting for the units of the
vertical being negative (positive down).  It should now put the data
on the scale correctly.

There is still no way to manually set the vertical scale.  I'll
put that enhancement on our TODO list.

Don Murray
> Regards, Nick
> 
> 


Ticket Details
===================
Ticket ID: LUU-266374
Department: Support IDV
Priority: Normal
Status: Open