Re: [OpenMap Users] Grid and zooming questions

From: Don Dietrick <>
Date: Tue, 14 Sep 2004 13:19:52 -0400

On Sep 14, 2004, at 11:14 AM, wrote:

> Hi,
> I've recently started to use openmap and, as a beginner, already run
> into
> several probems. So I wonder if some of you can help me out :-)
> First, I want to define a grid where each cell should have
> approximately
> equal area. The area (kmxkm) and the bounding box of the area are input
> parameters. Does openmap have any support for creating such grids? If
> not,
> can anybody give me a hint how to do this?

No, not really. A UTM or Lambert Conformal Conic projection would give
you that, but you'd still have to modify OMGrid to handle pre-projected
data. I think the easiest thing for now is to inverse project your
data back into lat/lon decimal degrees.

> For now on, I'm using OMGrid for displaying grid values on the screen.
> I've tested a 250x250 cells grid (65500 cells) and both displaying and
> redrawing were quite fast. However, I can zoom the area only once and
> after that I get OutOfMemory error. Does anybody know why?

What is your java heap set to? You should probably add a -Xmx256m
flag, or a bigger number, to the java launch script to give java more

You might also want to check and make sure your OMGridGenerator isn't
holding on to extra OMGraphics when the OMGrid is regenerated.

- Don

Don Dietrick,
BBN Technologies, Cambridge, MA

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Received on Tue Sep 14 2004 - 13:20:51 EDT

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