[postgis-users] selecting a time window

[tasneem dewaswala]

Hello,

I have following data with me

Msg         UTC_Time          Lat                      Lon

  1            133552.25      56.670042           12.862099
  2            133552.75      56.6700403333    12.8621025
  3            133553.25      56.670037           12.862107
  4            133553.5        56.670035           12.8621096667
  5            133554.25      56.6700311667    12.8621146667
  6            133554.75      56.6700303333    12.8621158333
  7            133555.25      56.6700295         12.8621173333
  8            133555.75      56.6700286667    12.8621181667

I need to do following operations
1) count the total number of messages within a 2 sec time window, for e.g.
msg 1,2,3,4 falls under 2 sec time window,
    similarly 5,6,7,8 in next 2 sec.
2) draw a linestring using lat/lon values in that 2 sec i.e line from msg 1
to msg 4.

i don't know how can i do this, please give me some suggestions
i am using c# for programming and my postgresql version is
"PostgreSQL 8.4.14, compiled by Visual C++ build 1400, 32-bit"
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/postgis-users/attachments/20130112/f4ee5fc2/attachment.html>