[GRASS5] i.points and i.rectify question

[Markus Neteler]

On Sun, Nov 16, 2003 at 08:31:42PM -0400, Bob Covill wrote:
> Hello,
> 
> There is a difference between i.rectify (& i.points) and i.rectify3. 
> Unfortunately, I have never figured out which one is "more" correct. I 
> think that i.rectify3 post dates i.rectify and was intended to replace it??
>
> The i.rectify3 and i.points3 programs both use the image3 library in 
> src/libes. This library utilizes the proj library and converts 
> coordinates on the fly between lat. long. and the users coordinate 
> system. Unfortunately, i.rectify3 is not built by default, but the 
> source is still there.

Some clarification (as far as I understood it):

#######################

Family "old" in 4.x:
- i.points (raster target map), i.vpoints (vector target map)
- i.rectify, i.rectify2
- imagery lib

Family "new-but-incomplete" in 4.x:
- i.points3 (aims at merging i.points and i.vpoints, introducing
             DEM support for LANDSAT ortho imagery)
- i.rectify3
- image3 lib (implements new methods, aims at integrating the 
  orthophoto stuff)

#######################

Family "old" in 5.x:
- i.points (raster target map), i.vpoints (vector target map)
- i.rectify (which is the code of i.rectify2 with fixes, old
             i.rectify deleted)
- imagery lib

Family "new-but-incomplete" in 5.x:
- see 'Family "new-but-incomplete" in 4.x' 
  with some fixes from Bob Covill

#######################

Summary 5.x: i.points works, i.vpoints works (a few bugs inside),
             i.rectify works

             image3 lib, i.points3, i.rectify3 may work, highly untested
             promising, contains tons of debug code, was left in a stage
             of uncompleteness.

> We probably need to decide which set of programs is more up to date (and 
> accurate). My preference has been i.points3 and i.rectify3 but I may be 
> way off on this.

I agree. But it will require some work, to get the promising image3 lib
functional. Efforts are welcome :-)

Markus