[visad] GOES AREA goerefencing

• To: <visad@xxxxxxxxxxxxxxxx>
• Subject: [visad] GOES AREA goerefencing
• From: Luis Martín Pomares <luis.martin@xxxxxxxxxxx>
• Date: Fri, 25 Mar 2011 14:54:16 +0100

Dear all,

I am trying to georeference GOES AREA files using visad. I am doing this in
MATLAB. However, I obtain strange value. I want to give the latitude and
longitude and obtain a row and column value to access the matrix of
radiances from [1,1]. 

In the example of visad it says I have to do the following:

af = new AreaFile("/home/user/mcidas/data/AREA0001");
dir=af.getDir();
nav=af.getNav();
GVARnav ng = new GVARnav(nav);  // XXXXnav is the specific implementation
  ng.setImageStart(dir[5], dir[6]);
  ng.setRes(dir[11], dir[12]);
  ng.setStart(1,1);

However w5 is a date, so I change the w5 by w6 and w7:

W6
image line coordinate of area line 0, element 0
W7
image element coordinate of area line 0,
element 0

I have tried to see the correspondence the point that I get for the sub
satellite but it is not ok. What I am doing is this:

clc;clear all;close all;
import edu.wisc.ssec.mcidas.*
file='D:\Irsolav\GOES\GOES_DATA\goes08.2000.303.144514.BAND_01';
data=AreaFile(file);

dir=data.getDir();
nav=data.getNav();

ng=GVARnav(nav); %XXXXnav is the specific implementation
ng.setImageStart(dir(6),dir(7));
ng.setRes(dir(11), dir(12)); %
ng.setStart(1,1);
ng.setMag(1,1);
%......................
disp('LINELE'); %subsatellite point for GOES 8
latlon=[0;-75]
linele_area=ng.toLinEle(latlon)

disp('LATLON TRANSFORMATION');
% linele=[1;1]
latlon=ng.toLatLon(linele_area)
%ng.toLatLon(double[][] linele);   %public abstract double[][]
toLatLon(double[][] linele)

disp('IMAGE COORDINATE TRANSFORMATION');
linele_image=ng.areaCoordToImageCoord(linele_area)

disp('Transformation from IMAGE coordinates to AREA coordinates');
linele_area=ng.imageCoordToAreaCoord(linele_image)

% disp('Transformation from IMAGE coordinates to AREA coordinates - version
2');
% linele_area=ng.imageCoordToAreaCoord(linele_image)

latlon=ng.toLatLon(linele_area)
%By convention, latitudes are positive North (negative South), and
longitudes are positive East (negative West).

• Follow-Ups:
  • Re: [visad] GOES AREA goerefencing
    • From: Tom Whittaker