[Freegis-list] Free GIS for realtime data and 3D visualization?
peter_7003 at yahoo.com
Fri Mar 9 15:33:33 CET 2007
Wow, thank you all for your answers.
Now I have so many choices, I have to find the best for me. Maybe you could help me? - Here is the scenario for those who are interested in:
We are evaluating whether a free GIS would be appropriate or something like Google Earth, NASA World Wind or ArcGIS. The problem with World Wind is that it is currently DirectX only, so not platform independent (migration to java and therefore platform independence is planned for end of april 2007). ArcGIS is expensive as is the enterprise edition of Google Earth and not open source. One advantage of Google Earth (GE) however would be the continuuous increasingly available card material (until they want money for that).
We have a horizontal table (desk) with a rear projection to visualize a map. Onto the table, there are tablet-pcs which visualize a zoomed portion of the underlying map (imaginable like a rectangular reading glass, but without the lens distortion of course). The tablets get their data via WLAN. What we want to do is to synchronize the tablet with the underlying map, i.e. when the user shifts the view on the table (e.g. using the mouse), the changes have to be communicated to the tablets so that they can change their view accordingly.
Additionally there is a vertical display. When the user selects an object on the table (or the tablet), the object should be displayed in a 3D view on the vertical display and be turnable by actions on the table/tablet (so ones can view it from every angle). One idea we had is to run one GE instance on the table and one on each tablet. Another idea is to use Google Maps for the table and GE for the tablets. When using GE on the table, would it be possible to get the KML data of the object out of the system for display on the vertical display? What if I want to use another viewer on the vertical display? Are there alternatives which are compatible to that?
Is there an event based mechanism in Google Earth to communicate these changes to the tablets? Or do I have to use polling or test for the mouse events in an operating system dependent manner? Furthermore we will receive realtime data (e.g. GPS positions from moving objects) and want to visualize this onto the table and the tablets.
There are two more approaches I can think of. One of them is the very promising WMS approach (thank you, Brent and Johannes!) where I dont know whether there are performance problems because of the realtime aspect (I have to test, or if anyone of you has already experience with that?..). The other is a local, monolithic, non-distributed GIS like GRASS GIS (thank you, Allan). Please correct me, if I am wrong. So for GRASS GIS I dont know whether it is modular so that the viewer can be run on the tablets and the map database could be run centrally so the viewers can access it simultaneously (does anyone know whether GRASS GIS is able to do that?).
And last but not least: documentation or help by such kind people like you all is an issue. So if anyone knows also something about this aspect of the GIS (free and the non-free ones) I would be thankful for hints.
So thank you for your help so far, I hope someone could answer some of my questions.
Best regards and till soon,
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