G.I.S. Prolog is a free Prolog interpreter, originally based on the "Prolog inference engine" (distributed by Prolog Development Centre in their Visual Prolog compiler package), but enhanced and extended with many new built-in predicates, a higher operation speed (mostly due to several Prolog predicates being implemented in optimised 32-bit Assembly Language), an improved Graphic User Interface and other important new features, e.g. "Clause Tree displays"; the innovative "Net Graph Designer Tool"; a fast, complete, but small "DCG language parser", etc. You can download and test G.I.S. Prolog by clicking here The current release of G.I.S. Prolog is version 1.02, which includes the latest DCG parser module. and a "point-inside-polygon" predicate, in_poly/3'. At present, G.I.S. Prolog is only a basic programming environment used by our company (ENB Ltd) to implement, test, and improve G.I.S. - related computing applications, Expert Systems, experimental A.I. and Data Mining. The G.I.S. source code we develop here, at ENB Ltd, is "declarational"; but also benefits from "brute force Assembly Language" implementations of Prolog predicates. (To see more details of this unusual Assembly Language development work, click  here). George A. Stathis (for ENB Ltd), 10 March 2005.

• Donwload the file "gis_prolog.zip", unzip its contents to a new directory of your choice, locate the unique executable file "PIE32.EXE" and (if you wish) place a shortcut to it on your desktop. (No other setup or installation is necessary).
  
• Thereafter, a click on the shortcut (or running "PIE32.EXE") causes immediate access to the G.I.S. Prolog interpreter.

G.I.S. Prolog version 1.02 features:

• Many new Predicates have been implemented in Hand-Optimised Assembly Language: - G.I.S. Prolog draws benefits from a vast repository: "Assembly Language Extensions for Visual Prolog", containing hundreds of Prolog predicates implemented in 32-bit Assembly Language (in "IDEAL mode" for TASM).
  
• G.I.S. is VERY speed-intensive! I am now working hard to improve the speed and performance of many new G.I.S-related Prolog instructions (e.g. "point inside polygon") written in Assembly Language, to process massive G.I.S. data at much higher speeds than commercial "G.I.S. software" (a lot of which is very slow!)
  
• The "Net Graph Designer Tool" is a novelty of G.I.S. Prolog, perhaps unique among Prolog interpreters, but still in its infancy: -This tool  facilitates the design, visualisation and creation of graphs (networks of nodes and edges), and it also generates the source-code that corresponds to each graph (through the button "generate", in the "Graph Design dialog window"). This facility of G.I.S. Prolog will soon become a viewport accessing a much larger (potentially infinite) "virtual G.I.S. map area" which may contain real G.I.S. landscapes, with polygons and other G.I.S. information, as defined (e.g.) in standard "Shape Files".
  
• Two important new G.I.S. predicates for reading shape-files have been implemented: shp_read/1 and shp_read/3).
• DCG Grammar Parser
• Clause-Tree display
• Some old bugs of the original "P.I.E. interpreter" (G.I.S. Prolog's ancestor) have now been corrected; most notably the hideous failure exhibited by the "call/1" predicate, inside existing clause-bodies, when calling (as an argument ) any predicate of zero arity.
  

G.I.S. Prolog version 1.02 index of predicates

• G.I.S. Prolog includes its own Source Code Editor. If you require help on any predicate or topic (for which help is available) while inside the Source Code Editor, you can mark any section of text by shading it with the mouse and then pressing "F1" for help. E.g. selecting "findall", F1 gives information about the predicate "findall". An alternative (context sensitive) help is also provided by right-clicking the mouse over a button for which help is required. 
• G.I.S. Prolog remembers all the previous files loaded into it, as well as various window sizes, etc.
  
• You can also modify the appearance of G.I.S. Prolog (including the fonts used, the window and dialog colours, etc) and your modifications will also be remembered.

• G.I.S. Prolog is free or "public domain", which means that you can download it, copy it, donate it, distribute it, and install it, anywhere, as you may please.
• However, the source-code of G.I.S. Prolog is not free, nor is it disclosed (at least currently; at the time of writing - February 2005).
• Future versions of G.I.S. Prolog are probably going to remain free, but we 're considering the possibility of releasing certain "specialised professional versions" in the near future (possibly also including source-code), which can be purchased or downloaded for a small fee.
• If you feel inclined to grumble about our "source code secrecy policy", please remember (to our credit) that we (at ENB) are a private company (and I am a freelance developer, affiliated to this company); i.e. we are not (e.g.) academics, able to sit back collecting a safe government salary, while distributing freely "open" source code which costed man-years to develop (or several years to ensure that it remains "State of the Art", by continual improvements and know-how updates). So...
  
• Our focus is on practical results from our A.I. research: - In this way, we can also guarantee that the technological solutions we developed for ourselves, can also be applied beneficially in cooperation to any other company with compatible projects in a variety of areas, both in the E.U. and throughout the World.
• Telephone support for G.I.S. Prolog is not offered. (Only participants in my personal Prolog seminars and/or close friends do get support, very occasionally. ;) )