Several Questions in GIS/Database

Hello, Dear netters:

        I have a new assigment involving GIS. I am doing GUI X/Motif programming for a while. The GIS is totally new for me. I have some questions for you. Hey, dudes. If these are the FAQ questions, then sorry to wasting bandwidth.         

1. What I understand GIS has three parts, they are maps, symbols and database. Am I correct?
2. Can you give me a list of the most popular GIS software run on Unix platforms(Sun Sparc(Solary 2.x or SunOS 4.x), HP-9000/7xx(HP-UX 8.xx), SGI(Iris 4.xx)). Works on X11R5 with Motif? If is possible also give me the list of names and phone numbers that company make these GIS products?
3. How does the GIS work? Can GIS software allows users add/delete/ modify the maps data? For example, I want to add some maps data into the database which are not available in comercial, a real estate agent wants delete some data, a city developer wants to modify the city streets, etc.
4. How to create your own symbol libraries? Dose GIS software come with some tools to do that? Can I create my own symbol libraries by using Xlib/pixmap/bitmap file?
5. How to input/extract the data to/from the symbol libraries? How to make color shape-fill on the maps with specify data?
6. What are the comercial database software support the GIS products? Oracle, Sybase, Informix, Ingres, dBase IV, etc.

6a)	Can a GIS software run with two or more different database software?
	For example, a host is a GIS server, a host is Oracle dababase sever,
	and other host is Sybase database server. Can you link your GIS server
	to either Oracle server or Sybase server.

7) 	How to create the maps data? By read the ASCII(text) files? by input
	the photo image? by the CAD drawing format(in what special format?)?
	Last year I saw that company GTE used AutoCAD draw the airport
	for the Air Force, then they extract the AutoCAD drawing format into
	the GIS database. They use this for airport fire emergency application.
	That was very interesting. Do you have any idea how to do that?

8) 	Are you using comercial GIS product(s) (like COTS) or using public 
	domain GIS software(like GRASS)?

9)	Have you ever think about real time GIS application? So far I see
	most of GIS application are mapping, enviroment, city develop-
	ment, 911 emergency, weather service, etc. These applications
	do not require real time. But our application are tracking target
	movement and display the graphics data. This is require the
	real time hardware/software. 

9a)	Have you see any GIS/graphics acceleration/real time board support
	Unix platform machines?

Enough questions for today! Hey dudes, you don't have to answer all the questions if you don't know all the answers. Just answer as much as you can. Please do not just follow-up on the USEnet, please also sent me a copy by email. Because I don't have too much time reading the news in USEnet.

        Thank you very much in advance, dudes!

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