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The data are processed. on a MODCOMP mini-computer.’ The MODCOMP system 
components consist of: 128K memory words floating point hardware, RAMTEK GX- 
100B graphics display unit, 25 megabyte disk drive, VERSATEC printer/plotter, 
magnetic tape drive, CRT terminals. 
Data Analysis Program 
  
The data analysis program is structured so that. any one of a set of 
routines can be called up. Each routine performs certain operations on the 
block of SRT scan data that have been read from tape to a disk partition. 
The available options include: 
3. Display data - displays earth curvature corrected data from a specified 
channel on the RAMTEK unit. 
2. Colour slicing - allows arbitrary assignment of colours to radiation 
intensity levels; this helps to discriminate details in the displayed 
scene. 
3. Point location - given the latitude and longitude of a point on earth, 
calculates its location in terms of pixel and scanline number within the 
data block, and the zenith angle of the point with respect to orbital 
track. 
4. Calibration - calibrates digital count vs. temperature (ch. 3, 4 or 5), 
or percent albedo (ch. 1, or 2) from calibration data of a given block of 
scanlines; atmospheric correction values can be input to obtain digital 
count vs. corrected temperature for ch. 4 and ch. 5 data. 
5. Process data for printing - a block of data is processed and stored for 
printing; the analyst specifies: size and location of data block, range 
of temperature to be output, spatial resolution and map scale of output 
data, resolution of the temperature field and digital count cut-off in 
ch. l-or ch. 2 data, if either channel is to be used to mask land 
surfaces in the temperature field. 
Print Program 
The block of processed data is output in alpha- numeric character code on 
the appropriate scale. Fig. 1 is a sample output of a 2x2 pixel averaged field 
on a 1:1,000,000 scale of Lake Ontario temperature. Starting with character 
"Q" for the temperature at the warm end of the range, the characters represent 
stepwise decreases in temperature toward the cold end of the range. 
The printout also contains unique symbols that replace certain grouped 
characters; this is done to facilitate analysis of tne temperature field (see 
Fig. 1 and Table 1). 
Data Presentation 
The temperature field is hand-analysed and the results are usually 
transferred to a standard map. Fig. 2 shows the analysed map for the Lake 
Ontario printout of Fig. 1. The alpha-numeric code in Fig. 1 covers a 
temperature range from 2.5 to 17.4 C. The code and both the ch. 4 indicated 
and corrected temperatures are listed in Table 1. 
Although the data have been rectified for earth curvature and rotation 
and for map projection, minor distortions of the data field, caused by orbital 
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