[GRASS-dev] wxGUI: supervised classification tool

[Vaclav Petras]

Hi Stepan,

On 21 December 2012 16:53, stepan.turek <stepan.turek at seznam.cz> wrote:
> Hi,
>
> yesterday I discussed some ideas on improvement of supervised classification
> capabilities in GRASS with Martin and a remote sensing researcher, who is
> working with proprietary software.
>
> We came up with suggestion that useful feature for GRASS would be
> interactive scatter plot tool which would allow to highlight pixels
> according to chosen areas in scatter plot and also in reverse way it would
> allow to highlight corresponding points in scatter plot for chosen areas in
> map window.
> Also it would plot class ellipses for training areas.
>
> Useful and unique feature among GIS and Imaginary software would be scatter
> plot 3D mode which would allow comparison of 3 bands.
>
If starting from scratch, Matplotlib seems to be the right option. It
allows to interactively select data and also draw 3D plots. Data for
scatterplot can be obtained by r.stats -g input=map1,map2. The result
needs to be stored and used for searching coordinates and values (i.e.
coordinates in scatterplot). Highlighting in plot according to click
in the map is probably possible. The other way should be also
possible, there are some click handler sin matplotlib. Highlighting in
map - that's probably something for your (Stepan's) new graphical
object API.

However, there is also Bivariate Scatterplot Tool available from Map
Display. It's able to display plots for pairs of maps. The plot is
wxplot which is not so powerful as matplotlib. I am not sure if it
could be used more interactively.

Vaclav

> Stepan
>
> ---------- Původní zpráva ----------
> Od: Anna Kratochvílová <kratochanna at gmail.com>
> Datum: 20. 12. 2012
> Předmět: Re: [GRASS-dev] wxGUI: supervised classification tool
>
>
> Hi,
>
> On Thu, Dec 20, 2012 at 9:52 AM, Markus Neteler <neteler at osgeo.org> wrote:
>> Hi,
>>
>> while searching for the new i.class tool I have discovered
>> the "supervised classification tool"
>> in Imagery -> Classify Image -> Interactive input for supervised
>> classification
>>
>> Nice! /edit: I now see that it *is* the
>> http://grasswiki.osgeo.org/wiki/WxIClass
>>
> Right, wxIClass (perhaps g.gui.iclass in the future), available as
> "Interactive input for supervised classification" from the menu, is
> intended to be an i.class replacement.
>
>> I tried it with NC data and loaded the Landsat2002 group.
>> Now I would expect that I can select channels for display from
>> the group. Perhaps something with [x] checkboxes would be
>> good. The existing "free" choice of maps should remain of course.
>
> That's reasonable, other suggestions are here:
> http://trac.osgeo.org/grass/wiki/wxGUIDevelopment/wxIClass
>
>>
>> When I then digitize, it nicely opens the class dialog, ok. Then,
>> when running, it segfaults (entire wxGUI disappears, no error msg
>> visible).
>
> There have been some changes three days ago which should fix this
> crash. If you used the latest version, we have a problem.
>
>>
>> Suggestion: It may also become the tool for i.smap, just a method
>> dialog would be needed
>>
>>> Run Analysis
>> - MaxLik: i.maxlik
>> - SMAP: i.gensigset, i.smap
>>
>
> yes, something like this is planned, Stepan is collecting these ideas now.
>
> We haven't touched this tool for some time, however Martin tried to
> use it in class with students this week and he promised to report
> bugs.
>
> Anna and Vaclav
>
>> to make it universal. However, great to have such a tool now.
>>
>> Markus
>> _______________________________________________
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>
>
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