[Mapserver-users] postgis and 4d data in mapserver

[Bob Basques]

>
>Sean, not to worry, this application is for monitoring aircraft noise in the
>neighborhoods surrounding an urban airport.  I won't make your plane crash.
>
>Mapserver would still only be used to create two dimensional maps.  For the
>animations, it would just end up being a series of maps shown sequentially
>(possibly the flights being swf files overlayed on the background image in a
>flash application) that showed where the flight is at a particular time and
>a tail of a certain time length trailing behind it.
>
I'm building something similar for a GPS tracking service that would use 
MapServer as the background.  I'm using DHTML though for the animation 
pieces.  There might be some overlap here.  I would be interested to 
hear more.

> For the elevation
>profile, I would just want to take the geometry from a line a user could
>draw on the map and query out what the elevations of the flights were and
>then any graph could be made elsewhere.  The main thing is to be able to
>have a database that I can easily query out the elevation and time
>information at points along the flight track as well as looking at the track
>as a whole. 
>
Very interesting idea.  so a cross-section (or at least where the 
flightpaths cross) of a user drawn line would be built based on data 
from the DB.   Hmmmm, how about adding in the different plane types 
(body styles as well) if they are in the database.

> Currently at my hands I have ArcSDE on top of Oracle (without
>the spatial extensions) and am looking to possibly to move to
>postgresql/postgis or oracle spatial to maintain this data.
>
I don't think you would be required to move to Oracle Spatial for this, 
it may help out down the road for integrating possible additional themes 
of data though.  All the functionality you describe could be built 
without a Spatial DB store, except of cource for locating the 
flightpath, which I assume is some set of points over time, similar to a 
GPS set of records.

>  It sounds like
>LWGEOMs may be able to work for me (would I be able to get the elevation at
>a certain place in the line where it intersects a line in two dimensional
>space?) in postgis, but I am far from locked into anything right now.  The
>basic point is to take a 2-d map, filter it by time, and use the powers of
>the database to drive other queries.
>  
>
The math to get the intersection is pretty straight forward, if you have 
a line for the section  and a flightpath line (or series of line 
segments in sequence with the time indexes attached.)  I would need to 
see an example of the data to be sure.

What about attributing the flightpath with a label that changes while 
the location changes.  These intersection points could be labelled for 
all flight paths and even a MAX/MIN/MEAN report generated for 
hiest/Lowest/ and average height of flightpath.  Do you have any Noise 
data, you could even add in a noise radius to the section view of the 
ground.   Actually, the same formulas used for displaying the points of 
intersection between the flightpaths and the section line, could also be 
used to show ground elevations with the addtion of a surface model DB 
(TIN file).

Hmmm, this sounds like a fun project.  Just let me know if you want me 
to make any more work for you.

:c)

bobb



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