[Xastir-Dev] NWS Radar Images

[Gerry Creager]

So what happens if we get the NexRAD products directly, and process the 
data in xastir to develop a composite image, rather than expecting NWS 
to do all the heavy lifting?  This data's about to become "widely 
available...."

gerry (the other one!)

Gerry Wheeler wrote:
> I was looking at the GIF images for the NWS radar, and I found something
> interesting. I'm wondering if Xastir has enough features to take
> advantage of it... 
> 
> The radar GIFs use a color pallette (as do all GIFs, I think), so each
> point in the image specifies a pallette index from 0 to 255, and that
> place in the pallette specifies the color. 
> 
> The adornments in the image, such as state lines, highways, labels,
> etc., each use a unique pallette index. So, if the pallette is modified
> to make the appropriate positions specify the color "black", all the
> adornments disappear. The result is an image that contains only the
> radar data, without extra stuff. 
> 
> I was looking at the code in maps.c that loads images based on .geo
> files, and I see there are numerous options that Xastir will feed to
> Image Magick to make conversions to the image. However, I don't know
> what they all do -- is there something that can be used to modify the
> image pallette? 
> 
> Another thing that might be done (or maybe already has been done) is to
> have Xastir treat the black parts of the image as transparent, so then
> the radar data could be drawn on top of other images. I seem to recall
> that there's a way in a GIF image to specify that one of the colors
> should be treated as transparent, so maybe that could be used. 
> 
> And finally (is this enough yet?), is there a way to tell Xastir to crop
> the image? It would be nice to remove the left edge where the scale is
> drawn. 


-- 
Gerry Creager -- gerry.creager at tamu.edu
Network Engineering -- AATLT, Texas A&M University
Office: 979.458.4020  FAX: 979.847.8578
Cell: 979.229.5301    Pager: 979.228.0173