[GRASS-user] Long post - Remote Sensing - Classifications

[Moritz Lennert]

On 26/02/09 13:58, mitch_TX wrote:
> On Wed, 2009-02-25 at 20:46 -0800, Hamish wrote:
>> ok so from the command line 'd.mon x0' should work to open a monitor,
>> and you could try the steps first from the command line (keep it simple).
>> If all works there you can move to trying launching it from a GUI.
>> i.class will always want to run in an xmon + console though.
>>
>> this gets i.class working for me using the sample Spearfish imagery
>> dataset:
>>
>> g.region rast=spot.comp
>> d.mon x0
>>
> 
> When I do that, I get the following warning using the wxPython GUI.
> http://n2.nabble.com/file/n2389455/dx0.png dx0.png 
> 


Hamish meant running these modules from the command line.

> That's the point. Isn't supposed to be a monitor display?
> "..divided into three parts. In the upper right corner you see the image. In
> the lower right corner, zoomed map portions will be displayed when using the
> zoom function. In the left section of the monitor, histograms for the
> selected training areas for all channels will be displayed. The training
> areas can be digitized...." 
> (Neteler, M., H. Mitasova 2008, pp. 320-321)

Again, this is when run from the command line using the x-monitors (i.e. 
d.mon).

> No. They are general simple windows displaying info regarding coordinates
> and Digital Number values like:
> 
> Diplay: #
> R:# G:# B:#
> Proj: UTM ZONE
> Map: #, # meters
> Lat Long: DD, DD
> 
> Moving the cursor on 2 linked displays you have the same geo-info
> (you are supposed to link 2 linkable displays) but different RGB values
> (generally 2 -- or more -- different bands or color composition are loaded
> on different displays).
> The meaning of this is allowing a visual inspection (in terms of either
> different color composition or shades of gray) of the same area, supported
> by a numerical info (DN -- therefore a precise representation of the
> reflectance behavior of different surfaces).
> I don't know if I made myself clear..I can show you a couple of screen-shots
> as soon as I get to the department (it's going to be Envi and Erdas
> though...I hope you guys don't mind "commercial" images on this forum :-))

In the wxGUI, if you display the two raster in the same Map Display, 
select both of them in the layer manager and use the query tool in the 
Display, you get the numerical information on both maps. But you have to 
open another Map Display if you want to _see_ both maps.


>> or even a static d.what.rast?
>>
>> I am not sure what you mean by that.
>> maybe r.what does what you want?
>>
> 
> 
> In order to use r.what you are supposed to use a separate file containing
> the points you are querying, right?
> No, this is not exactly what I'm talking about...or better, the outcome is
> but it's not the interaction that I'm looking for. I'm talking about a
> pointer based like d.what.rast one.

You have the query tool in the Map Display of the GUI.

Moritz