[GRASS-dev] [GRASS GIS] #1984: i.pca should accept also group names as input (like r.out.gdal)

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#1984: i.pca should accept also group names as input (like r.out.gdal)
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Reporter: neteler | Owner: grass-dev@…
     Type: defect | Status: new
Priority: normal | Milestone: 7.0.0
Component: Imagery | Version: svn-trunk
Keywords: i.pca r.out.gdal | Platform: All
      Cpu: All |
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When analysing multispectral data, it is common and convenient
to use an imagery group as input instead of a list of raster
map names.

The r.out.gdal module supports both raster map and group names
input, the same approach is desired for i.pca.

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Ticket URL: <http://trac.osgeo.org/grass/ticket/1984&gt;
GRASS GIS <http://grass.osgeo.org>

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#1984: i.pca should accept also group names as input (like r.out.gdal)
------------------------------+---------------------------------------------
Reporter: neteler | Owner: grass-dev@…
     Type: enhancement | Status: new
Priority: normal | Milestone: 7.0.0
Component: Imagery | Version: svn-trunk
Keywords: i.pca r.out.gdal | Platform: All
      Cpu: All |
------------------------------+---------------------------------------------
Changes (by neteler):

  * type: defect => enhancement

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Ticket URL: <http://trac.osgeo.org/grass/ticket/1984#comment:1&gt;
GRASS GIS <http://grass.osgeo.org>

3

#1984: i.pca should accept also group names as input (like r.out.gdal)
------------------------------+---------------------------------------------
Reporter: neteler | Owner: grass-dev@…
     Type: enhancement | Status: new
Priority: normal | Milestone: 7.0.0
Component: Imagery | Version: svn-trunk
Keywords: i.pca r.out.gdal | Platform: All
      Cpu: All |
------------------------------+---------------------------------------------

Comment(by mmetz):

Replying to [ticket:1984 neteler]:
> When analysing multispectral data, it is common and convenient
> to use an imagery group as input instead of a list of raster
> map names.

An imagery group as input is accepted as of r56494.

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Ticket URL: <http://trac.osgeo.org/grass/ticket/1984#comment:2&gt;
GRASS GIS <http://grass.osgeo.org>

4

#1984: i.pca should accept also group names as input (like r.out.gdal)
-------------------------------+--------------------------------------------
Reporter: neteler | Owner: grass-dev@…
     Type: enhancement | Status: new
Priority: normal | Milestone: 7.0.0
Component: Imagery | Version: svn-trunk
Keywords: i.pca, r.out.gdal | Platform: All
      Cpu: All |
-------------------------------+--------------------------------------------
Changes (by hamish):

  * keywords: i.pca r.out.gdal => i.pca, r.out.gdal

Comment:

in the case of i.pca, do the order of map inputs matter? order within the
group may be predictable, but is it guaranteed long-term?

Hamish

ps- AFAIK it's undocumented, but trac parses keywords on commas
internally.

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Ticket URL: <https://trac.osgeo.org/grass/ticket/1984#comment:3&gt;
GRASS GIS <http://grass.osgeo.org>

5

#1984: i.pca should accept also group names as input (like r.out.gdal)
-------------------------------+--------------------------------------------
Reporter: neteler | Owner: grass-dev@…
     Type: enhancement | Status: new
Priority: normal | Milestone: 7.0.0
Component: Imagery | Version: svn-trunk
Keywords: i.pca, r.out.gdal | Platform: All
      Cpu: All |
-------------------------------+--------------------------------------------

Comment(by mmetz):

Replying to [comment:3 hamish]:
> in the case of i.pca, do the order of map inputs matter? order within
the group may be predictable, but is it guaranteed long-term?

The order does not matter for the output maps (PC scores), but does matter
for the vectors (loadings), since each loading refers to a specific input
band.

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Ticket URL: <https://trac.osgeo.org/grass/ticket/1984#comment:4&gt;
GRASS GIS <http://grass.osgeo.org>