July 20, 2005

EarthImagePlugIn: Part 2

After playing around with the EIPI I saw they were moving around large buffers (actually int arrays) which caused lots of memory bloat and some lags in performance. I was hoping I could provide just a BufferedImage as an OMRaster, but unfortunately when the sub-image is generated on a change of projection the EIPI needs to generate an OMRaster that conforms to that projection. For example, when dealing with an Orthographic projection you need to warp the image (raster) yourself.

The current EIPI does this by iterating over every pixel of the projection, converting these to Lat/Lon points, and looking up pixel values from their cached image based on the calculated degrees per pixel and each Lat/Lon point from the projection.

I just think there has to be a better way.

Posted by Guy at 05:21 AM | Permalink | Comments (0)

July 17, 2005

EarthImagePlugIn

I was playing around with OpenMap's EarthImagePlugIn [bbn.com] this weekend, which I must say is really cool, and I noticed that it used a lot of memory and was kind of slow. Of course I was using a 7.5MB gif image of the world, but I have another image that goes up to 31.5MB.

I wondered about where the performance bottlenecks and memory bloat were coming from, so I took a look at the PlugIn code. It seems that it's not utilizing any Java 1.4+ imaging functions, such as the ImageIO class. I replaced their image loading method with an ImageIO call and memory usage dropped significantly. I didn't do any timings, so I couldn't check the performance gains, but I think I would have recognized any significant speedups.

I also noticed un-optimized translation routines in the ImageTranslator inner-class. I'll try and help that out too.

Posted by Guy at 06:03 PM | Permalink | Comments (0)

May 19, 2005

OpenMap Layer Tutorial: Part 1

I've completed (almost) the first tutorial describing how to use the OpenMap framework. It's located off of my main site [lunaflare.net]. Hopefully this won't be the last.

Posted by Guy at 08:58 PM | Permalink | Comments (0)

May 14, 2005

OpenMap Tutorials

I've decided to write some stuff on how to develop for OpenMap [openmap.org]. It's really a great toolkit that is extendable as all get-out. Professionally I use it every day and personally I use it for simple mapping applications. Anyway, the first tutorial will be how to write a simple layer for display. More on this later.

Update: I wrote these tutorials and put them on one of my business sites [hazelnutcafe.net].

Posted by Guy at 06:48 PM | Permalink | Comments (1)