4 million sounding data

[Jason FU]

Well, but I only have the sounding data from the users. The point is I
am investigating how to set a display limit for MapServer by selecting
only part of the points well distributed all over the waters. I cannot
sort out the way to get the "current" extent {(minx, miny) and (maxx,
maxy)} during zoom-in for a proper SQL statement for both PostGIS and
Oracle 10g.

Any suggestion?


Jason