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The DEC GIGI terminal has 8 colors or 8 grey shades and a screen with resolution 768 horizontally by 240 vertically. Price with a black & white monitor is about $2800, and with a color monitor, about $3500. Through the courtesy of the local DIGITAL office, I was able to make a test plot on the GIGI to verify the correctness of the <PLOT79> interface, and it might be of interest to record my experience. The plot chosen was the 3-color plot DEM66 which shows a hidden-line view on which contours are superimposed; the surface is enclosed in a box with labelled 3D axes, and the contours are also displayed on the top and bottom surfaces. CPU time for construction of the plot on the DEC-20/60 was 77 sec. The plot was transmitted from our DEC-20/60 via a 1200-baud dialup connection, and took approximately fifty (50) minutes to complete. The plot file contained 19497 vectors represented in 329195 characters. This gives an average transmission rate of about 1100 baud. Editing with EMACS to remove NULs and CR LF characters reduced the size to 245039 characters (74.4% of original). During editing, I noticed the presence of duplicate vectors (due to coordinate roundoff into the same pixel); a small utility program showed that there were 1545 duplicate vectors (7.9% of original). Compacting could thus have reduced the file to about 66% of its original size, and elimination of successive points on the same straight line would further reduce it by a undetermined amount. The GIGI will not keep up with transmission above 4800 baud, so a reasonable time estimate at that speed (with file compaction) might be about 8 minutes. Halving the grid size in the array could further reduce this to perhaps about 2 minutes. Clearly, such action would be necessary to make the plotting time acceptable. The vector format of the GIGI looks something like !P[nnn,nnn]V[nnn,nnn] !V[nnn,nnn] for a move then draw, and for a subsequent draw, respectively. A similar verbosity is found in the Tektronix 4025 intelligent terminal. Eleven characters (plus two more for CR LF) are on average sent for one visible vector. The data format used in the Tektronix 4010 series is more compact, but not human-readable, since it packs a 10-bit coordinate into the low-order five bits of two characters; the high-order two bits in each character are used as flag bits, since it is possible to omit unchanged chunks. It is therefore interesting to compare with the plot file produced using the Tektronix 4010 interface and subsequently processed by the TKVECS utility. The 4010 file took 124932 characters (38% of GIGI file). It contained 83296 NULs (for delay time padding at 9600-baud transmission rates), leaving 41636 non-NUL characters, and had 11681 draw commands and 3443 move commands. There were 682 duplicate commands and 5578 points on the same line. Elimination of the NULs indicates that a vector on average requires about 2.75 characters, about 25% of the number required by GIGI or the Tektronix 4025. Thus, despite the awkward format of the Tektronix 4010 vector file, there is a substantial storage and transmission time reduction. During plotting on the GIGI, I noticed that when a colored line crossed a white line, there appeared to be color bleeding into several adjacent pixels on the white line. The GIGI User's Manual revealed the reason -- there are only 3 color bits and 1 blinking bit in graphics memory for 12 adjacent pixels on a raster line. This resulted in the red contour lines broadening into a 12-pixel wide band on the blue surface; when the lines run diagonally, the width on the screen is 2 to 3 mm. I personally find this quite objectionable, since it seriously reduces the resolution when color is used.