[GRASS-user] new to GRASS

GRASS GRASS user
,
1

hi all
can anybody tell me what is command d.extend used for ?
till ystrday i was nt able to display a .tif file even after setting region for raster but then i gave the d.extend command after d.rast and was able to display the image on x mon0
I dont know if d.extend really helped to display the contents of the .tif image as earlier i was just able tos ee a black screen on the xmon
not the contents…
anyways thanx to all
i am able to display the image now ,n now trying to explore more of GRASS
savitri
DEAL,India

On Mon, 22 Jan 2007 Otto Dassau wrote :

Hi,

On 22 Jan 2007 07:18:00 -0000
“savitri negi” savitrinegi1@rediffmail.com wrote:

hello all
iam quite new to GRASS infact i started it jst a few days back

i downloaded the source GRASS 6.2.1 source code n compiled it on my redhat
enterprise linux machine and i was able to start GRASS
n started using it.
i also istalled the two mandatory gdal n other library

now say i want to display just a .tif image i did the following
i selected the database a location and a mapset at startup screen after
which i was able to see the GIS manager GUI
i have got say a .tif image.
1 …converted the .tif image into raster using r.in.gdal input=filename.tif
output =output raster image name
2 …started the monitor x0 as d.mon x0

using d.mon you might need a further step here to set the extend of your current
region to the tif before you display it.

g.region rast=output_raster_image_name

hth,
Otto

3 …tried to diplay image on mon using d.rast= outut raster image name

but iam unable to see anything in the x0 monitor though the whole process
dint showd any errors
though wen i change the background color in d.rast window i can see a
coloured surface of size of my original image on x0 but not the real image
,being quite new to the GIS field iam not able to figure out wat am i missing
.
right now i just wanted to display a tif image or may be a .img file on the
monitorr
which iam not able to do
may be anyone of u could help

Savitri negi
DEAL,india

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2

savitri negi wrote:

can anybody tell me what is command d.extend used for ?

As the manual page and --help text says:

       d.extend - Set window region so that all currently displayed raster,
       vector and sites maps can be shown in a monitor.

The effect is similar to e.g. "g.region rast=..." except that it uses
the set of maps currently displayed on the current monitor rather than
having the user specify which maps to use.

till ystrday i was nt able to display a .tif file even after setting
region for raster but then i gave the d.extend command after d.rast
and was able to display the image on x mon0

One potential issue is that a monitor can have its own current region
which may not match that set by g.region. It may be necessary to run
d.erase after changing the region with g.region, in order to clear any
region stored on the monitor.

[The reason for having a separate region on the monitor is that you
can divide the monitor into multiple "frames" with d.frame, and each
frame can have a different region.]

--
Glynn Clements <glynn@gclements.plus.com>