[Xastir] More on radar problem

[Alex Carver]

It's a poor hack but it works enough if I can find accurate markers (like junctions in highways) since those should have identical coordinates no matter what software is being used.  I only need anchor points, not much else.

--- On Sun, 12/6/09, Gerry Creager <gerry.creager at tamu.edu> wrote:

> From: Gerry Creager <gerry.creager at tamu.edu>
> Subject: Re: [Xastir] More on radar problem
> To: "Xastir - APRS client software discussion" <xastir at lists.xastir.org>
> Date: Sunday, December 6, 2009, 11:40 PM
> I'll find the explicit reference (all
> I can find is the full-US mosaic right now) but using
> Delorme is a real poor hack since the projections are
> different between RIDGE and Street Atlas.  At least
> from a GIS geek perspective.
> 
> gerry
> 
> James Jolin wrote:
> > Alex Carver wrote:
> >> --- On Sun, 12/6/09, James Jolin <jjolin at itol.com>
> wrote:
> >>  
> >>> Alex,
> >>> How did you set up the geo file?  Did you
> take an
> >>> existing file and change the url or did you
> start from
> >>> scratch?  I know next to nothing about
> geo files.
> >>> Jim
> >>> WA9ARB
> >>>     
> >> 
> >> The easiest way is to follow along with one of the
> default GEO files and make the appropriate modifications.
> >> 
> >> Here's an example of my GEO for the Atlanta area
> RIDGE radar (watch out for word wraps):
> >> 
> >> #             
>          X     
>          Y     
>          Long   
>         Lat
> >> URL     http://www.srh.noaa.gov/ridge/RadarImg/N0R/FFC_N0R_0.gif
> >> TIEPOINT           
>     0           
>    0           
>    -87.37500   
>    35.58083
> >> TIEPOINT           
>     620         
>    620         
>    -82.00217   
>    31.14133
> >> IMAGESIZE 620 620
> >> REFRESH 60
> >> TRANSPARENT 0x0
> >> PROJECTION LatLon
> >> 
> >> The TIEPOINT directives will assign a specific
> pixel coordinate (X,Y) to a specific lat/long.  Pixel
> 0,0 is upper left, and 620x620 is the lower right most pixel
> on my RIDGE image (the image itself is also 620x620 in this
> case).  You need two TIEPOINTs so that Xastir can
> appropriately place the image.  The IMAGESIZE tells
> Xastir how big the radar file is in pixels (again 620x620
> for the Atlanta RIDGE).
> >> 
> >> After that, just fix the URL accordingly.
> >> 
> >> The more accurate the points, the better the radar
> will line up with your maps.  I used Delorme Street
> Atlas to find a couple known points in the RIDGE data and
> then worked my way back to the corners.  You don't have
> to use the corners of the image file, any two points will do
> since Xastir knows about the overall image size using the
> IMAGESIZE directive.
> >> 
> >> You may have to play around with the TRANSPARENT
> directive which tells Xastir what color is defined to be
> transparent for overlay purposes.
> >> 
> >> 
> >>   
>    _______________________________________________
> >> Xastir mailing list
> >> Xastir at lists.xastir.org
> >> http://lists.xastir.org/cgi-bin/mailman/listinfo/xastir
> >> 
> >>   
> > thanks, Alex...looks like a nice evening project.
> > Jim
> > 
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