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Author Topic: Polygons only... points and lines need not apply. :)  (Read 661 times)

Boyd

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Polygons only... points and lines need not apply. :)
« on: February 11, 2018, 03:42:16 PM »
Here's a project I spent a lot of time on a few years ago, then lost interest and forgot all about it. I pulled the source files off my computer because they were taking up so much space, and now it appears that I erased the drive they were archived on. So everything, including the custom software I wrote is now gone and only the map itself remains. Easy come, easy go! ;)



This map is now available for download for the amusement my fellow mapmakers and advanced users: https://www.gpsfiledepot.com/maps/view/786

It really highlights the difference in rendering engines across Garmin's product line. Kind of surprising how the Montana mangles it (looks like a watercolor sketch of a map). My guess is that Garmin plays a little loose with the math to speed up some of their devices. Can't really blame them of course, I'm doing things they never intended to support with their map format. :)

« Last Edit: February 11, 2018, 06:41:20 PM by Boyd »

Brek

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Re: Polygons only... points and lines need not apply. :)
« Reply #1 on: February 11, 2018, 10:45:25 PM »
Nice :)
There was a program about that converted sat imagery to vector map, presumably using polys.
I did a sat map that even worked with 60csx.
Long time to render, but better than expected result once the screen was drawn.


Boyd

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Re: Polygons only... points and lines need not apply. :)
« Reply #2 on: February 12, 2018, 05:32:24 AM »
Thanks. :)

Yes, there are a couple, one of them is called MOAGU (Mother of All GPS Utilities) and the author is a member here. However this is a bit different because I did not convert anything to an image. The polygons that make up the map are different types of landcover. The state has a dataset where they have traced areas on the map and assigned codes to them, such as deciduous forest, low density housing, industrial complex, etc. I just used these polygons and assigned colors to them based on aerial photography.

I tried this map on my 60csx, and it does work but I don't think it looks very good - here's an example.


Brek

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Re: Polygons only... points and lines need not apply. :)
« Reply #3 on: February 12, 2018, 10:26:19 AM »
Still not bad 60csx.
Are the bottom two examples the same display resolution as the images you posted appear to be?
I wonder if they cheated on interpolation for the display, or rounding with integers somewhere for a slower processor.

Boyd

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Re: Polygons only... points and lines need not apply. :)
« Reply #4 on: February 12, 2018, 12:49:01 PM »
Are the bottom two examples the same display resolution as the images you posted appear to be?

I assume you mean the comparison of the Nuvi 3550 and Montana 600? The Montana screenshot is at its native resolution of 480x272. The Nuvi 3550 has a native resolution of 800x480, so I scaled that to 480x288 to match the height of the Montana image. The screenshot at the top of the page shows the full 800x480 resolution of the Nuvi.

Garmin just released their first outdoor gps with a 5" 800x480 screen last year, the GPSMap 276cx. it has been very controversial and problems with early units really alienated some of their loyal customers, many of which returned them. Hopefully they are addressing these issues, but some people feel the processor is just too slow to provide decent performance. Looks like a nice device, but for $600 I'll pass. ;)

With this map, I have found that it looks ok on almost any Garmin device IF you zoom in far enough. So while that screenshot on the Montana looks terrible at .3 miles, at the 500 ft. zoom it's OK.

But really, these devices like the Nuvi 3xxx are probably just an anomally in Garmin's line. The higher quality rendering doesn't make much difference with the maps that Garmin sells. :)