Originally Posted by latchodrom
I think that a grid of 10 M square with wpt each 0.5M will do the job.
Is this a step in the right direction?
If you are on Windows, then you can try:
1. Download the zipped archive from search_grid.zip - 4shared.com - online file sharing and storage - download
2. Unpack the contents into a convenient folder, say "Desktop/SAR"
3. While running OpenCPN
drop a waypoint in the location where you want to center the pattern
4. Go to Route Manager->Waypoints and Export this waypoint into the SAR folder, giving the file the name "start.gpx", maybe overwriting the existing one.
5. In Windows Explorer go to this SAR folder (or make a suitable shortcut before) and run the application sar2gpx.exe. It will create the file "sar_grid.gpx" in the same folder.
this file into OpenCPN - this is your 10 mile grid with 0.5 mile resolution
There is a gotcha:
- if you import it as Temporary Layer, it will be easy to delete or hide these 441 waypoints later on, and the points will be locked from accidental change...
- if you import it as GPX file, it will be possible to use the precision assured by "Use nearby waypoint?" when creating routes...
Not a truly rock-solid solution, but more or less what you asked for. It will not work (yet) across the Date Line and very near the Poles.
I thought about indicating somehow which quadrant - relative to the center - the WPs are in by different icons (NW,NE,SE,SW). Always can be done.
If you are not on Windows, I have to learn a bit more or maybe some Python soul will help...