[GRASS-user] Rotate a map display

[Cuinet Jérôme]

Thanks for your responses,

I realize that I don't need a GIS such as Grass which is like other GIS a 
system intended for geographic database users, not for map users.

I need a map server, and so I think that MapServer is a better solution for 
my needs


----- Original Message ----- 
From: "Hamish" <hamish_b at yahoo.com>
To: "Jérôme - GeoRezo.net" <jerome at georezo.net>; "Vincent Bain" 
<bain at toraval.fr>
Cc: <grass-user at lists.osgeo.org>
Sent: Thursday, April 16, 2009 9:39 AM
Subject: Re: [GRASS-user] Rotate a map display



Vincent wrote:
> If you need to warp a map for a strict display purpose, IMHO it's
> not to be performed from within grass given that this operation
> makes no sense "geographically".

I agree,

> Don't know what the context is, but if you just have to rotate an
> image output of a map maybe you'd better look towards image
> manipulation tools (e.g. imagemagick and the -rotate option, which
> can easily be integrated in a script process).

pnmrotate is another that I've used with d.out.gpsdrive and GpsDrive's
gdal_slice.sh script, together with 'g.region -n' to get the convergence
angle. (angle between local projection north vs true north)


render map with PNG driver in GRASS, read course-over-ground from Gpsd
(gpsd.berlios.de) in watcher mode, pnmrotate and pnmcrop, and then use
an image viewer which will update the display when the image changes.
(see grass 7 discussions about that).


Hamish