4. INTERACTIVE GRAPHICS SYSTEM ON ANALYTICAL STEREOPLOTTERS 
Using above mentioned new techniques and devices, we can 
build a full-functional interactive graphics system on an 
analytical stereoplotter to edit digital maps on-line, dis- 
regarding the capacity and the performance of the mi crocom- 
puter which controls the analytical stereoplotter. Such 
system should provide following functions: 
--- Using zoom and pan features to display any part ofa 
digital map, which has been created by that analyti cal 
stereoplotter and stored on the disk, in detail. 
--- Adding any line, curve, polygon, or annotation (text) 
anywhere to the digital map. 
--- Deleting any object. from the digital map. 
--- Moving, rotating, or scaling any object on the digital 
map. 
--- Changing the attributes (e.g. color, linestyle, etc.) 
of any primitive on the digital map. 
--- Filling any area on the digital map by fill pattern. 
--- Digitizing an existent map or picture and adding it to 
the digital map. 
--- Producing a quick check-plot of the digital map on the 
printer. 
--- Selecting to update the old file of the digital map, to 
creat a new file, or to leave the digital map unchanged 
after editing. 
The system should be user-friendly and respond promptly. 
In case of operator's mistake, the system should display a 
warning message only, instead of hanging up or breaking 
down. | 
5. EXAMPLES 
Two interactive color graphics systems have been desi gned 
and programmed by the author and are nou in operation in 
Tai wan R.O0.C.): as; ;well as in Saudi Arabia. 
5.1 Zeiss Pl ani comp 
The manufacturer does not provide any interactive graphics 
capability on Zeiss Planicomp /4/. Thanks to the high per- 
formance HP1000 A900 computer, which controls Plani comp, 
and the HP AGP (Advanced Graphics Package) software 131, 
the author has been able to design an on-line interactive 
graphics system to edit the digital maps created by Zeiss 
Planicomp /1/. The harduare used by this system consists 
of a HP2627A color graphics terminal and a HP9111A graphics 
tablet (Fig.3). The RTE-A operating system /6/ with CDS ( 
Code and Data Separate) and VM (Virtual Memory) features 
provi des nearly unlimited capacity in both data memory and 
program length. The AGP software supports all new techni- 
ques of interactive graphics mentioned in this paper /5/. 
This example shows a software-oriented system. 
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