[GRASS-user] Help

GRASS GRASS user
1

Hello :smiley: My name is Patricia and need help with GRASS. Will be visible if you
help me find some information about the GRASS operation:D So I need to know
:
1.What is the proper sequence of the basic elements of the GRASS
hierarchical data structure?
2.Does g.region have mandatory parameters? If yes, then specify what ?
3.To open multiple graphical monitors, command line mode allows the GRASS
system ?
4.What is the full (obligatory) syntax of a command that allows you to
display basic GRASS layer information?
5.How do you know the parameters of a region assigned to a raster layer
called powiats? Enter a command or command to let you know.
6.The command syntax along with the appropriate parameter to display the
vector layers available in the system?
7.Command name and its mandatory parameters to display a composite image
composed of three RGB color channels. Layer names can be fictitious
8After changing the working area (computational), this information should be
passed to the graphical command line mode window. Give commands that you can
use
9.To test how many pixels in the raster layer have a given average value,
use the command
Along with the parameters (flags):
10.
Write the command syntax along with the formula (raster map calculator),
which will give you a new raster floating point class, called alpha, as a
result of the formula calculation:
alfa=(2⋅sin(srednia"\_"beta))/3
11
Write a command syntax that will allow you to calculate the TVI vegetative
index. The input layers are landsat_band3 and landsat_band4.
TVI=√((NDVI+0.5) )
I really needs help because nobody at all does not want to give me any
information:/

--
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2

Hi Patricia,

On Tue, Jun 6, 2017 at 9:16 PM, Szalona P <Patrycja2131@onet.pl> wrote:

Hello :smiley: My name is Patricia and need help with GRASS. Will be visible if you
help me find some information about the GRASS operation:D

Much is covered here:
https://grass.osgeo.org/grass72/manuals/index.html

and nice tutorials are here:
https://grass.osgeo.org/documentation/tutorials/

So I need to know :
1.What is the proper sequence of the basic elements of the GRASS
hierarchical data structure?

You can find that here in a graphical view:

https://svn.osgeo.org/grass/grass/trunk/doc/grass_database.png

and more detailed here:
https://grass.osgeo.org/grass72/manuals/helptext.html#2.-background:-grass-gis-location-structure

2.Does g.region have mandatory parameters? If yes, then specify what ?

In general no, it can run with a single flag like "-p" for print the
current region.
See
https://grass.osgeo.org/grass72/manuals/g.region.html

3.To open multiple graphical monitors, command line mode allows the GRASS
system ?

You can use
d.mon wx0

see
https://grass.osgeo.org/grass72/manuals/d.mon.html

4.What is the full (obligatory) syntax of a command that allows you to
display basic GRASS layer information?

d.rast rastermap
d.vect vectormap

5.How do you know the parameters of a region assigned to a raster layer
called powiats? Enter a command or command to let you know.

g.region raster=powiats -p

6.The command syntax along with the appropriate parameter to display the
vector layers available in the system?

g.list vector

7.Command name and its mandatory parameters to display a composite image
composed of three RGB color channels. Layer names can be fictitious

d.rgb ... :slight_smile:

8After changing the working area (computational), this information should be
passed to the graphical command line mode window. Give commands that you can
use

d.erase

9.To test how many pixels in the raster layer have a given average value,
use the command
Along with the parameters (flags):

There are different possibilities, eg with r.mapcalc or r.stats or others.

10.
Write the command syntax along with the formula (raster map calculator),
which will give you a new raster floating point class, called alpha, as a
result of the formula calculation:
alfa=(2⋅sin(srednia"\_"beta))/3

Similar to what you wrote but be sure to have white space left and
right from the " = " sign.

11
Write a command syntax that will allow you to calculate the TVI vegetative
index. The input layers are landsat_band3 and landsat_band4.
TVI=√((NDVI+0.5) )

Check i.vi and r.mapcalc.

I really needs help because nobody at all does not want to give me any
information:/

HTH,
Markus

--
Markus Neteler, PhD
http://www.mundialis.de - free data with free software
http://grass.osgeo.org
http://courses.neteler.org/blog

3

Szalona P wrote:
..

2.Does g.region have mandatory parameters? If yes, then specify what ?

Markus Neteler:

In general no, it can run with a single flag like "-p" for print the
current region.
See
https://grass.osgeo.org/grass72/manuals/g.region.html

If you execute something like `g.region --` or `g.region
--help` in the command line, you'll get a "help" text including a "Usage"
mini-section:

Usage:
g.region [-dsplectwmn3bgau] [region=name] [raster=name[,name,...]]
   [raster_3d=name] [vector=name[,name,...]] [n=value] [s=value]
   [e=value] [w=value] [t=value] [b=value] [rows=value] [cols=value]
   [res=value] [res3=value] [nsres=value] [ewres=value] [tbres=value]
   [zoom=name] [align=name] [save=name] [--overwrite] [--help]
   [--verbose] [--quiet] [--ui]

Everything inside [square brackets] is optional. Everything outside, is a requirement.
This applies to all modules.

@All, I wonder if a global --usage flag, for all modules, would make sense. One
example would be `g.region --usage`.

Nikos

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