Introduction to Remote Sensing (Page 6):

Additional types of data

Now let's take a look at some of the details of Honolulu so that we know what we are looking at in detail. This part of the "tutorial" is very similar to some of our Virtual Field Trip of SE Oahu , so that you may want to check out those pages too.

Thematic Mapper Simulator Image [Full Size: 800x460 JPEG]

Here we see a version of the TMS image of Honolulu that makes the image look quite similar to how we would observe the city from an airplane. As with our Virtual Field Trips, we have a number of buttons (1 to 6) that you can click on to see the area at higher resolution from a low altitude aircraft. The area in the red box shows the spectral study area that we saw on Page 4.

Shuttle Imaging Radar [Full Size: 818x545 JPEG]

By chance, the exact same part of Honolulu that we see in the TMS data was also imaged by the SIR-C imaging radar. This system, as you may know, shows steep slopes and rough surfaces (at a wavelength of 24 cm) as very bright parts of the image, and smooth or non- reflective surfaces as dark. Again, we have links you can click on to take you to the low altitude photography that will help you see what you are looking at.

Oblique View of Honolulu
[Full Size: 650x287 JPEG]

Sometimes it is valuable to look at an area from a perspective that is not straight down. All spacecraft images of Hawaii are obtained looking down from 210 - 830 km above the Earth, so that to get a different view we have to use a computer to recreate a new picture. We do this with the aid of a digital topographic map and a SPOT satellite image of Honolulu. Within the computer, we can increase the relative heights of the features (inducing a "vertical exaggeration" to the image) so that we can see more clearly what the landscape is like.

In this set of three images, we inter-compare the oblique computer image with photographs taken from our aircraft flying along the coast. We have numbered several places in the different views so that you can locate yourself in the images. Note that these numbers are not linked to any other images -- they just help define the same features.

Go on to Page 7 to experiment with your own band combinations for our Honolulu image, or go back to Page 5.

Author: Pete Mouginis-Mark

Copyright by P. Mouginis-Mark

Curator: Lori Glaze