[GRASSLIST:2826] Re: Please Help for Digitization

Eric G. Miller egm2 at jps.net
Thu Dec 27 23:19:40 EST 2001

On Wed, 26 Dec 2001 17:47:10 +0530 (IST), Anil Kumar Bhagat <anil at ces.iisc.ernet.in> wrote:

> Dear Sir ,
>            Marry Christmas.
> How are you ? After a long time I am writing you . I have some  problem in
> map registration . My problem is as following .

Happy Holidays!

> I want to digitize the map with the help of module   < v.digit > . I use
> mouse .
> problem No. 1
> --------------
> After filling map information its shows the following messege 
> writing plus file ...
> But after this it directly goes on MAIN MENU . It doesnot ask for map
> registration . So I am not able to registered the scaned topo sheet map.

Well, v.digit is not for registering images, it is for digitizing vectors.
If you need to register the map, look at i.points or i.vpoints and i.rectify.
Details can be found in the image processing tutorial available from the
GRASS website.

> Second problem .
> ------------------
> I scaned the topo sheet to generate vector layer . With the help of
> Customize menu when I try to display the  scaned map  with the help of 
> BACKDROP  CELL MAP utility ,but  map doesnot appear . But any map from
> spearfish database  appear . The scaned topo sheet map I imported & I am
> able to display it with the help of raster display . 

Your second problem is probably related to your first.  If the scanned
image is not registered, but you entered real coordinate boundaries at
the start of v.digit, then the two will probably never overlap (therefore,
it doesn't appear).  See about registering the image, and then the rest
should be okay...

Eric G. Miller <egm2 at jps.net>

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