It looks like i.rectify processes the complete target area instead of just the image area to be rectified.
If I want to restrict the calculations to the area of interest, can I use r.mask or should I create a target location of only the area of interest?
I would rather use r.mask, since I could change the mask depending on the area of interest. If that won’t work, then I will create subset locations for each image or flight line.
Thanks to Giovanni and Moritz. Your information is what leads me to believe that I must restrict calculations to the area of interest in order to make better use of computing resources.
x-y location
g.region -p
projection: 0 (x,y)
zone: 0
north: 4171
south: 0
west: 0
east: 3280
nsres: 1
ewres: 1
rows: 4171
cols: 3280
cells: 13680880
Target location
g.region -p
projection: 1 (UTM)
zone: 4
datum: nad83
ellipsoid: grs80
north: 2401345.47908
south: 2350807.60197392
west: 574439.74229936
east: 640164.771271
nsres: 1.2962086
ewres: 1.29619826
rows: 38989
cols: 50706
cells: 1976976234
Luis E. Menoyo
U.S. Geological Survey
677 Ala Moana Blvd., Suite 415
Honolulu, HI 96813
lemenoyo@usgs.gov
808-587-2428
|
Moritz Lennert <mlennert@club.worldonline.be>
01/19/08 10:32 AM
|
On 19/01/08 00:25, Luis E Menoyo wrote:
>
> I'm using 1st order and 13 GCPs on an image and i.rectify has been
> running over 3 hours. Is the process locking up or is this amount of
> time normal in image rectification? Is i.rectify processing just the
> area of the image to be rectified, of is it calculating for the whole
> target mapset area? In other words, should I have applied a mask to the
> target mapset before running the georectify tool in order to cut down on
> processing time?
What are your region settings in the target location, especially the
resolution ? This can make an enormous difference in terms of
calculation time.
Moritz
>
> Any info would be greatly appreciated.
> Thanks!
>
> Image info:
>
> +----------------------------------------------------------------------------+
>
> | Layer: D-10@PERMANENT Date: Fri Jan 18 08:17:14
> 2008 |
> | Mapset: PERMANENT Login of Creator: me |
> | Location: x-y
> |
> | DataBase: /gis/oahu_flightlines |
> | Title: ( D-10 )
> |
> | Timestamp: none
> |
> |----------------------------------------------------------------------------|
>
> |
> |
> | Type of Map: raster Number of Categories: 255
> |
> | Data Type: CELL
> |
> | Rows: 4171
> |
> | Columns: 3280
> |
> | Total Cells: 13680880
> |
> | Projection: x,y
> |
> | N: 4171 S: 0 Res: 1
> |
> | E: 3280 W: 0 Res: 1
> |
> | Range of data: min = 0 max = 255
> |
> |
> |
> | Data Description:
> |
> | generated by r.in.gdal
> |
> |
> |
> | Comments:
> |
> | r.in.gdal input="/gis/oahu_flightlines/D/D-10\ |
> | .jpg" output="D-10"
> |
> |
> |
> +----------------------------------------------------------------------------+
>
>
> Computer:
>
> Mac Pro 2.66GHz, 2 dualcore Intel Xeon (4 cores total), 4Gb RAM
>
> GRASS:
>
> GRASS 6.3.0RC4 (2008)
>
>
>
> Luis E. Menoyo
> U.S. Geological Survey
> 677 Ala Moana Blvd., Suite 415
> Honolulu, HI 96813
> lemenoyo@usgs.gov
> 808-587-2428
>
>
> ------------------------------------------------------------------------
>
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