Saturday, February 9, 2008

Using GSAK Arc Filters - Part I

Enough of Webby's warm and fuzzy stories! Let's get geeky again!

Just a short time ago, I explained the basics of using a GSAK point filter and then extended that to including multiple points in a filter. With a few clicks of the mouse, it's easy to move on to an arc filter -- similar to's "caches along a route", but working from your offline GSAK database. (In fact, before introduce the oft-requested "caches along a route", this was pretty much the only way you could do it.)

We’ll start with a real simple one. You notice that the two points I used before in Schaumburg and Lombard have a north-south road that nearly connects them. For the sake of this example, let’s assume that I plan to travel on that road, and as I travel from Schaumburg to Lombard, I’m willing to go about 1-1/2 mile off my route to find a cache. So this example is very simple. In the filter, I will select “Arc/Line” instead of “Points”, and will limit my distance to 1-1/2 miles.This gives me 44 waypoints, all within 1-1/2 miles of the black line on the map which connects the two points of the arc. In this simple example, since I only have two points, it doesn't matter in what order I list them in the filter.

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Webfoot said...

I'm assuming, and that could be a very rash assumption on my part, that since this is a part one, there's going to be a part 2 for multiple arc points?

Jim said...

The frog is wise.