Using Data from MOLA

Author: Matthew J. Simoneau

The Mars Orbiter Laser Altimeter (MOLA), an instrument aboard NASA's Mars Global Surveyor, collected 27 million elevation measurements in 1998 and 1999. Here, we work a medium-resolution dataset that the project produced.

Contents

• Loading the Data
• Projecting the Data onto a Robinson Projection
• Projecting the Data onto a Globe
• Creating a High-Resolution TIFF

Loading the Data

% Download the data.
filename = 'megt90n000eb.img';
resolution = 16;
if isempty(dir(filename))
    url = ['http://pds-geosciences.wustl.edu/geodata/mgs-m-mola-5-megdr-l3-v1/mgsl_300x/meg016/' filename];
    disp('Downloading.  This will take a while.')
    urlwrite(url,filename);
end

% Read in the file.
f = fopen(filename,'r','ieee-be');
el = fread(f,[360*resolution Inf],'int16')';
fclose(f);

% Down-sample the data.
el = el(1:4:end,1:4:end);
resolution = resolution/4;

Projecting the Data onto a Robinson Projection

axesm robinson
meshm(el,[resolution 90 -180],size(el));
framem on
gridm on
axis off
set(gca,'position',[0 0 1 1])

Projecting the Data onto a Globe

cla reset
axesm globe
meshm(el,[resolution 90 -180],size(el));
colormap(hot)
axis off vis3d
view(3)
shading interp
material([0.3 1 0])
camlight
set(gcf,'color','black')

Creating a High-Resolution TIFF

../mola.tif

set(gcf,'InvertHardcopy','off','PaperPositionMode','auto','PaperOrientation','portrait')
print(gcf,'-r600','-dtiff','mola.tif')

Published with MATLAB® 7.4