Which Geo stack for an online strategic wargame?

Question

I'm googling around for some weeks but I've some difficulties to figure out where to begin my project and which part of the available Geo stacks are mandatory for my needs.

I have a strong Java background, some interest for Python and totally open to learn some new technologies.

As an hobby and because it is close related to my job, I plan to develop a web MMO strategic wargame heavily based on an interactive maps (basically to display the tactical situation and give orders to units).

Here is what I was thinking about :

• Geoserver to serve maps and layers.
• PostGIS to store geodatas.
• GeoExt to display in a browser
• Apache Click as the Java application server (combat resolution, unit management)

I managed to deploy a GeoServer (war in tomcat, easier is difficult) I managed to install PostGreSQL I run some tutorials about GeoExt. I need to experience Javascript a little bit. I played with Apache Click to serve pages and forms.

Here is the flow I was thinking of :

• GeoServer serves the map backgrounds and layers constructed from PostGIS data for static objects (Cities, Victory Points, Territories, ...)
• Apache Click generates HTML+GeoExt pages in the client browser.
• Apache Click sends CRUD commands to PostGIS in response of user's action.
• [something] updates regularly PostGIS (movements, combat resolution, unit characteristics management...)
• Apache Click generates dynamically KML files to live update the browser (KML NetworkLink ?) for units display with icons, zones (range, detection...)...

And now, the missing brick in my little wall :

• How can I implement a "sea/land" layer. For example, to invalidate a ship movement passing on land ? GeoServer layer ? Zones defined in PostGIS ?
• Is the following flow reactive enough to update the map after a user action : HTML/GeoExt event -> Apache Click process -> PostGIS update -> GeoServer layer update -> HTML/GeoExt display

The main point is : where are the data if I want to use it for calculation and update ? GeoServer static layer or PostGIS tables ?

Answer 1

To answer the How can I implement a "sea/land" layer question.

You can get coastline and sea layer from the recently released Nature Earth v2.

It might be too accurate for your needs but with some generalisation you will be able to load this into postgis and define it as sea or land. Then your ship movement can be contained (http://www.postgis.org/docs/ST_Contains.html) an vice-versa with tank movement. Air would be a different path and more complex as you would need to know the current location and work out a nearest land airfield or aircraft carrier for re-fueling (unless air-to-air re-fuelling is allowed..)

Good luck with developing the game.

http://www.naturalearthdata.com/blog/miscellaneous/natural-earth-v2-0-0-release-notes/

Download area http://www.naturalearthdata.com/downloads/

Answer 2

You would likely update the post gis through proceedure calls from your server. For one thing all the geography stuff is not necessary and introduces a lot of compllexity and it would be very laggy and processor intensive for even one user. You could have a land and sea polygon within a layer and add say a +1 column in the table for sea rows and a -1 column for land. if the lat lon returned from a location event was a plus or minus it would trigger a rule that would invalidate the move for sea or land unit. You could use a digital elevation model as well with z level as a plus or minus. Games commonly have terrains but that does not mean they are built using GIS! I would study how a popular game engine handles terrains and how developers create those terrains, choose your favorite open source game. In my case it is BZFlag ; )