Friday, January 25, 2008

Using GSAK Point Filters - Part II

In my previous post, I showed how to use a simple GSAK point filter. As you saw, it did pretty much the same thing as filtering based on distance from your centre point, but you're not restricted to using your centre point or, for that matter, any cache in your database. The point filter can be based on any arbitrary lat/long you wish (although it's obviously useless to pick a lat/long outside of the area covered by your database).

Now, let’s do the same thing with multiple points. Let’s say I’m going to be at the Marriott in Schaumburg for a day, then I’m going to be in Lombard the next day. I’d like to find caches near both locations and load them at the same time, so I’ll be all set for my trip.

Using Maporama again, I find that the lat/long for the location I’ll be in Lombard is 41.887 , -88.018. So, I just add that to the same filter in GSAK. (Remember, you can click on the image here to see a bigger view of it.)

You can see that the list of points now includes TWO lat/long combinations. When I apply this filter, I now get 79 waypoints – 17 more than I did for just the Schaumburg filter.

When I plot those on a map, I now have two clusters of waypoints – one set within 3 miles of the green flag in Schaumburg, and another set within 3 miles of the yellow flag in Lombard.

It doesn't get much easier than that!

Coming up next: Arc filters

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