T/G Layout 1

CO M P U T E R SI M U L AT I O N

1. The APT images you have been working with are rectangular, 640 pixels wide by 480
   pixels long. How many pixels compose the image?


2. Pretend that you are a computer that will analyze several bytes of information. You will
   be presented with a table of 24 x 36 pixels. How many bytes of data is this?
   How many bits of data?

To determine your transmission rate per minute, enter your start time.

3. Shade the figure according to the information on page 205. When acquiring an image
   from a NOAA satellite in descending orbit, the satellite image will appear one line at a time
   from top to bottom. That is, all 26 pixels in the top row are colored in first. Then the second
   row is completed, and so on.

Write the time when you completed the shading.

4. What is your bit rate? (How many squares–pixels–could you fill in per minute multiplied
   by eight bits per pixel.)


5. NOAA satellites transmit data at 120 lines per minute. How does this compare with your
   personal transmission? Remember, you have 34 lines by 26 pixels.


6. What cloud patterns might be detected from your observations?


7. From your map, can you determine if any precipitation might be occurring?

name

Imagine a broadcast of infrared data from a NOAA satellite descending from the North Pole in the
morning hours. The observed image must be encoded and then sent as a radio signal. The entire
image seen is actually made up of tiny squares called picture elements or pixels.

The brightness of each pixel is assigned by a number value between 0 and 255. In this system,

0 represents pure black (warmest)

255 represents pure white (coldest)

all values in between are shades

of gray

1 pixel = 1 byte = 8 bits

1 p ixel is electronically transferred as 1 byte

1 byte equals 8 bits of data