Geoscience Reference
In-Depth Information
We can replace the default colormap by any other built-in colormap. Typing
help graph3d
lists the available colormaps. As an example we can use
imshow(I4,map)
colormap(hot)
to display the image with a black-red-yellow-white colormap. Typing
edit hot
reveals that
hot
is a function creating the
m
-by-3 array containing l oating-
point values between 0 and 1. We can also design our own colormaps, either
by manually creating an
m
-by-3 array or by creating another function similar
to
hot
. As an example the colormap
precip.m
(which is a yellow-blue colormap
included in the topic's i le collection) was created to display precipitation
data, with yellow representing low rainfall and blue representing high
rainfall. Alternatively, we can also use random numbers
rng(0)
map = rand(16,3);
imshow(I4,map)
to display the image with random colors. Finally, we can create an indexed
color image of three dif erent colors, displayed with a simple colormap of full
intensity red, green and blue.
Gallery
8.1
[I5,map] = rgb2ind(I1,3);
imshow(I5,[1 0 0;0 1 0;0 0 1])
Typing
imwrite(I4,map,'unconform_rgb.jpg')
saves the result as another JPEG i le.
8.4 Importing, Processing and Exporting LANDSAT Images
h e Landsat project is a satellite remote sensing program jointly managed
by the US National Aeronautics and Space Administration (NASA) and the
US Geological Survey (USGS), which began with the launch of the Landsat 1
satellite (originally known as the Earth Resources Technology Satellite 1) on
23rd July 1972. h e latest in a series of successors is the Landsat 8 satellite,
launched on 11th February 2013 (Ochs et al. 2009, Irons et al. 2011). It has
two sensors, the Operational Land Imager (OLI) and the h ermal Infrared