#1992: wxNviz: confusing to add raster3d isosurfaces
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Reporter: hamish | Owner: grass-dev@…
Type: enhancement | Status: new
Priority: normal | Milestone: 6.4.3
Component: wxGUI | Version: svn-releasebranch64
Keywords: wxnviz | Platform: Linux
Cpu: x86-64 |
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Hi,
I'm testing volumes in wxNviz, using the vox50 example from the wiki:
http://grasswiki.osgeo.org/wiki/3D#Examples
It's working, but I find the adding-isosurfaces part a bit counter
intuitive, and the 3D view was completely blank until I figured out to
manually change the viewing height. For the isosurface the main confusion
was because it works the opposite way to the [Submit] button when editing
vector attributes- there you edit first then hit the "go" button. With the
isosurfaces you press the [Add] button first, it creates a new isolevel
using the minimum data value, then you change the value from that default
by hand and just sort of press enter or change the field somehow and it
applies the change silently.
(maybe a "go" button to the right of the Isosurface level: text entry box
would help even if it did very little besides be yet another way to apply
the change? sort of like close-door buttons on elevators which don't do
much but are satisfying to press anyway)
Until I figured out I was looking at it all backwards it was all rather
confusing.. at first I typed in a value "1000.0" then pressed [Add], and
my 1000 was replaced by a 2.5 (the min value) in both the text entry box
and the level list. I kept on overwriting the previously entered value
adding new "2.5" value levels to the end of the list. Obvious in hind-
sight, but it's quite easy to get lost in it when just starting out.
-- Perhaps the fix for this confusion is to simply grey-out the
"Isosurface value:" entry box until at least one isosurface has been added
with the [Add] button? Then you get the order of buttons to press in your
mind from the beginning.
Also just to mention a bit of a bug to look out for: after adding
isolevels out of order and moving them up and down in the list, 2 of 4 iso
surfaces never rendered. Adding new isosurfaces at nearby (+/-) levels
rendered ok. No error messages. It's a little hard to reproduce, I'll post
back in a new ticket if I can figure out how to trigger it every time.
Perhaps the value is still sitting at 2.5 (default,minimum) instead of the
2000, 3000 showing in the surface level list (??).
Finally, for that data (spatial range is 0..50 in x,y,z) the default
viewing height is 5000 if you have no other map layers open, so you see
nothing in the display until you realize to manually type in 25 or 50 into
the Height: slider control. For cases when 3D view mode starts with 3D
rasters alone loaded, could it take a hint from the current region's
top/bottom value, or perhaps the first raster3d's values for the same, as
to what to set the starting min/max height around? (also, in this case the
old Tcl/Tk NVIZ default value of perspective=40 starts it out in a better
view than the new wxNviz default of =20)
thanks,
Hamish
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Ticket URL: <https://trac.osgeo.org/grass/ticket/1992>
GRASS GIS <http://grass.osgeo.org>