[GRASS-user] Lambert Conformal Conic location

GRASS GRASS user
1

Hello dear grassusers,

I'm triying to define a new location for a volume with this data:

Lambert Conformal projection:
  Standard Latitude 1: 60.000000
  Standard Latitude 2: 30.000000
  North/South Pole Row: -61.842026
  North/South Pole Column: 19.503059
  Central Longitude: 85.000000
  Column Increment: 90.000008 km

In 6.3-cvs.

It's a grid over Florida of 34 rows and 40 cols.

I'm selecting this option on the shell-script menu:

D
'Florida location'
projection: lcc
datum: nad27
parameters: 1
Central Parallel:36N
Standart Parallel 1: 60N
Standart Parallel 2: 30N
Central meridian: 85W
False easting: -61.84
False northing: 19.50

After I make the input above that i don't know if it's correct, i try a
region from 40N 0S 0W 34E, 1 res n-s, 1 res w-e (because I know previously
that the grid is 34x40), but I need to obtain the correct parameters for
the region with the parameters of the projection... I can't calculate the
grid dimensions for the region which adjusts my map... i can't see it.

Anyone can suggest a solution? Maybe I don't understand the region
concept... what are the units which I define the region: meters, pixels,
degrees...? I wonder if I must calculate the boundaries manually,
converting lcc information to x/y.

Thanks in advance.

Miriam

--
-------
<>
<> Miriam España Acebal
<> Ingeniera en Informatica / Computer Science Engineer
<> Departamento de Fisica Aplicada / Applied Physics Department
<> G. I. Fisica Atmosferica / Atmospheric Physics Research Group
<> Universidad de Granada / University of Granada
<> España / Spain
<> mespana at ugr.es
<>
-------

2

Hola Miriam,

Miriam ha scritto:

I'm triying to define a new location for a volume with this data:

Lambert Conformal projection:
  Standard Latitude 1: 60.000000
  Standard Latitude 2: 30.000000
  North/South Pole Row: -61.842026
  North/South Pole Column: 19.503059
  Central Longitude: 85.000000
  Column Increment: 90.000008 km

In 6.3-cvs.

It's a grid over Florida of 34 rows and 40 cols.

I'm selecting this option on the shell-script menu:

D
'Florida location'
projection: lcc
datum: nad27
parameters: 1
Central Parallel:36N
Standart Parallel 1: 60N
Standart Parallel 2: 30N
Central meridian: 85W
False easting: -61.84
False northing: 19.50

After I make the input above that i don't know if it's correct, i try a
region from 40N 0S 0W 34E, 1 res n-s, 1 res w-e (because I know previously
that the grid is 34x40),

Maybe I'm wrong, since I've never worked before with this kind of projections within GRASS, but the bounding box that you have just set begins at O°West and ends at 34°East. However, the central meridian for your data is 85°West. So I suppose your data is around this meridian, not between 0°-30°.

I can't calculate the
grid dimensions for the region which adjusts my map... i can't see it.

Try:
# g.region rast=your_map -g

and you will set the region to fix your map and also you will see what's really your data's bounding box. After that, you should be able to visualize your map:
# d.mon x0
# d.rast "your_map"

Anyone can suggest a solution? Maybe I don't understand the region
concept... what are the units which I define the region: meters, pixels,
degrees...?

The region units can be seen in the "YOUR_LOCATION/PERMANENT/PROJ_UNIT" file

I hope it will help.
Salu2,
Roberto.

Ps: También puedes enviarlo al lista en español, así generamos algo de tráfico en la lista :wink:

--
Roberto Antolín Sánchez
Politecnico di Milano – Polo Regionale di Como
(Laboratorio di Geomatica V2.8)
Via Valleggio, 11 – 22100 Como, Italy
tel: +39 031 332 7533 || fax: +39 031 332 7519
email: roberto.antolin@polimi.it

3

Hola Roberto,

Maybe I'm wrong, since I've never worked before with this kind of
projections within GRASS, but the bounding box that you have just set
begins at O°West and ends at 34°East. However, the central meridian for
your data is 85°West. So I suppose your data is around this meridian,
not between 0°-30°.

Ok. That point of view is obviously correct over the data projection.

Try:
# g.region rast=your_map -g

and you will set the region to fix your map and also you will see what's
really your data's bounding box. After that, you should be able to
visualize your map:
# d.mon x0
# d.rast "your_map"

I cannot do it, because I can import the map without define the location
previously. I detected that the moule r3.in.v5d imports so many rows and
columns as has the region, for what I must calculate it first (I think so).

The region units can be seen in the "YOUR_LOCATION/PERMANENT/PROJ_UNIT"
file

I hope it will help.
Salu2,
Roberto.

Ok! Thanks! :).
Saludos!

Miriam.

Ps: También puedes enviarlo al lista en español, así generamos algo de
tráfico en la lista :wink:

P.D.: Vale :), empiezo a reescribir .
--
-------
<>
<> Miriam España Acebal
<> Ingeniera en Informatica / Computer Science Engineer
<> Departamento de Fisica Aplicada / Applied Physics Department
<> G. I. Fisica Atmosferica / Atmospheric Physics Research Group
<> Universidad de Granada / University of Granada
<> España / Spain
<> mespana at ugr.es
<>
-------

--
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4

Hello Miriam and all,

Try:
# g.region rast=your_map -g

and you will set the region to fix your map and also you will see what's really your data's bounding box. After that, you should be able to visualize your map:
# d.mon x0
# d.rast "your_map"

I cannot do it, because I can import the map without define the location
previously. I detected that the moule r3.in.v5d imports so many rows and
columns as has the region, for what I must calculate it first (I think so).

The first time you didn't say that your map is a 3draster map ;). May be the problem is that, that is, you didn't set the top-bottom limits.

Anyway, are you sure it is impossible to import the data? I'm not sure but I think you can define a default location, and then you can import and visualize your map by setting the exact region. At least, it was possible when I tried with some other r.in.* modules some weeks ago. If you are able to import your map with r3.in.v5d and a "default" location, try this:
# g.region raster3d="your_3dmap" -p3

So you should see your 3d-region.

Cheers,
Roberto.

--
Roberto Antolín Sánchez
Politecnico di Milano – Polo Regionale di Como
(Laboratorio di Geomatica V2.8)
Via Valleggio, 11 – 22100 Como, Italy
tel: +39 031 332 7533 || fax: +39 031 332 7519
email: roberto.antolin@polimi.it