is WWJ the right tool for this job?

[otomotion]

I'm looking for a nudge in the right direction.

I'd like to build a sort of client/server application. The client would basically be for displaying information to users and I know WWJ would be great for that.

Server side, I need to retrieve information about particular lat/long. In order of importance, this information includes:

1. land or water
2. elevation
3. political association (ie. what country does this coordinate belong to)

I've briefly come across things like shapefiles and land masks. Anyone familiar with anything of this sort? There's nothing to satisfy point 1 in WWJ right? As for elevation, it'll depend on what has been cached, but the serve app isn't graphical, so are there other ways of updating my cache?

I'm new to WWJ.

thanks

[patmurris]

Can you describe in more details what you want to do ?

With a little help (coding) WWJ can display a lot of information coming from remote servers or local files. As to how to serve those in the first place, it depends a lot of the original data format and other considerations...

Please tell us more.

[withak]

A land mask is just a two-color map of the earth, one color for land and one for water. You convert your requested lat/lon to pixel coordinates in the image and check the color of that pixel on the map. You can do the same thing to identify countries (or any other geographic information that might be represented by colors in an image), though the precision is limited by the resolution of the image and the number of available colors.

You can do the same thing with a shapefile containing polygons by checking which polygon contains the requested coordinates. This requires more coding, but can be a lot more precise than retrieving information based on pixels in an image.

Elevation you can probably get from WWJ directly without having to do anything with your own data.

Thanks for the explanation withak.

patmurris, basically, my server could be compared to some sort of game engine that uses real world data. so it would need methods like:

getElevation(lat,long)
isWater(lat,long)
country(lat,long)

i guess it's worth noting that these don't necessarily require high resolution. they should, however, be consistent. that is, if i call getElevation for a particular coordinate i would like it to always return the same thing, so i guess i'd want to be working off a 'fixed' data source, if that makes sense.

isWater could ignore lakes and rivers and only consider large bodies like oceans if it simplified things.

isWater is the most urgent at the moment, i'm really looking for simplicity implementation-wise over resolution.

geonames.org has some webservices that might be useful, particularly for country determination.

usgs could be helpful for elevation.
http://gisdata.usgs.net/XmlWebServic...on_Service.php

[patmurris]

If you dont need much resolution, then maybe you could just code isWater() and country() in the client, using land masks has described by withak.

Anyway, for other data you would have to code both for the server and for the client to retrieve the data for WWJ to display. So your question is more about where/how to find these data and how to serve them to a WWJ client - is it ?

[TomServo]

Wouldn't it be easier for you two to meet up at a bar and discuss this over a few drinks? (Seeing as you are in the same location)

[patmurris]

You are right Tom, i didnt notice.
Otomotion: i'll setup an informal beer drinking conscious WWJ user/dev meeting soon in Montreal. If you feel like joining, check this thread :
http://forum.worldwindcentral.com/sh...ad.php?t=11012

[TomServo]

This is turning into the WWJava "Think Tank" meeting

[Chiss]

Too bad the Great Old One lives too far to join us!

[patmurris]

I wish there was some kind of video irc/chat channel where we could pop up at times and just chat live... wasnt that supposed to happen with year 2k ? We used to be able to do it with CuSeeMe... But then you need a usb beer dispenser too.