FlexLogger - Map Help Needed

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  • Updated 3 weeks ago
Hi All,

I've had a number of requests to include mapping in FlexLogger.   I know lots of programs do have maps.  Some do a great job with them as well. 

I'm not a cartography expert and there are some issues I have yet to solve with respect to providing good mapping in FlexLogger.  

I am appealing to the community to see if there are any folks out there that can provide suggestions, perhaps some mathematical support, etc to get the maps in FlexLogger to work well.

Here is the basic issue:  Map distortions.

If you google "map orange peel" you will find a ton of stuff talking about the difficulty of showing our world on a flat surface.

Add to that issue the fact that our Earth wobbles and the orbit is eccentric the computations to do good mapping become complex.

Here is my goal with mapping:

1) I want to show a relatively accurate sun and shadow to help people hoping to work the graylines.
2) I want to plot on the same map your home QTH
3) I would like to plot on the same map a perspective contact station
4) I would like to draw a line between them and show antenna angle and distance.

At this point in time I picked a rather inaccurate Mercator map.  I am able to plot the sun and shadow on this map with probably some major inaccuracies due to the map.  Here is what it looks like currently:

The red dot is obviously the sun.   Its position and the shadows are reasonably accurate near the equator but as you move further north and south things get out of wack.

For example the blue square is supposed to be my QTH roughly in Denver, Co.  But it plots more like I'm right on the border with Canada.

The issue here is simply that since our Earth is a globe and if we try to unroll it into a flat projection we run into a fair number of inaccuracies and it makes it difficult to plot things on the map.

I believe that google maps/earth apply some special corrections depending up on the projection they are using but google also has a ton more developers than I have (1).

Obviously one solution to this issue is to switch to a 3D globe and plot the maps and sun shadows on that globe.  The issue is the work factor.   It is probably 10x more difficult to do something nice in a 3D fashion.  It may still happen but not anytime soon.

So I am looking for help in two distinct areas:

1) I think the map I chose to use, while nice looking, is severely inaccurate enough to make plotting things difficult.  So I would like help to find and select a better map.

2) Once we pick a better map, there will still be some inaccuracies likely.  I'd like some help in ironing out the computations to plot things on the new map.

Thanks in advance

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Mark - WS7M

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Posted 3 weeks ago

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Mike - VE3CKO, Elmer

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I wonder if Darren KE9NS would be willing to contribute some his expertise as he has been there and done exactly this with his PowerSDR upgrades. He has gotten a lot of support from FRS and perhaps he may want to give a little back to the 6xxx users. I think it certainly is worth a try. Perhaps point you in the direction you need to go.