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Messages - Brek

#16
Map Making Support / Re: Simplifying World Map
January 24, 2017, 08:17:10 AM
Hi Boyd,
Yes, that’s half of the World map, and there’s another half to complete it.
I assume they are hosted here to be downloaded, and used on a Garmin GPS,
so what’s the difference if I use it on my own GPS?
Someone else might use it with Cgpsmapper since I believe that has a positioning function if you have a GPS mouse connected to a laptop.

Hi popej,
I wish I’d known earlier :D
I don’t think it’s going to matter in future. I wouldn’t want to do this to any detail map.
Just the World map is not intended to be zoomed into detail.
It probably would have been better though. There’s no brains behind skipping ever x number of points,
but for a world map at very high zoom, I don’t think any difference would be perceived.

Back to the other thing...
I would like to distribute a few sample map tiles in future, but I’m far from that stage yet.
I’d like to get in touch with “RoboMatt” who made the Garmin Yosemite too hosted here.
I’m only talking about a small tile cut out of that, have either of you any way to contact him?
I couldn’t see any posts here for that name.
This world map, I’m not satisfied to stick with that data for any future stuff.
If it came to it I’d trace from a world map to get a single clean line around
continents because the screen is so small.

If or when it does come to distribution of any of my software, sample tiles would be nice,
but aren’t required.
The program that I used to simplify the world map is the same that does the pre-process for my GPS.
The user could do that themselves.
Cheers, Brek.
#17
Map Making Support / Re: Simplifying World Map
January 23, 2017, 05:16:56 PM
Ok, well it appears Cgpsmapper doesn't have the feature, but I've written a program to
process the mp file that Cgpsmapper produces.
When parsing any line element, I included the first point in the line, and then only included
one in every five points, until the last point which is always included.

This would normally work a treat, but for the world map, some extra bodge is needed because
it appears to be automatically produced using a raster map as the source.
There are a large number of little lines with only two or three points all abound the continents,
so I also excluded any line with only two or three points.

#18
Map Making Support / Simplifying World Map
January 22, 2017, 05:16:55 PM
Greetings from Australia folks :) This is my first post here.

My question relates specifically to the World topo map available here,
of which I think there is only one. It comes in two packages for East and West parts of the world.

I'm writing GPS software for a relatively small screen, and was hoping to use this world outline for a basemap.
I have stripped the low zoom image down with Cgpsmapper to just the line type 0x15
(for shorelines), so it's just the simple continent outlines that are left on the map.

The problem is the map is still far too detailed, and I was hoping there's a way in Cgps mapper, to lower it's resolution (number of points) automatically.
I have found a feature called "Generalise" which does that, but not significantly,
and you can only use it once on a map. There are still a few tens of thousands of lines.

One obvious way would be to retrace the map with simpler lines, or to delete a bunch of existing points,
but it would be ideal if there was an automated way.
Any ideas appreciated.
Cheers, Brek.