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Author Topic: Nuvi 2757 SATELLITE IMAGERY? Last chance for non-android GPS  (Read 1699 times)

jubatus

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Nuvi 2757 SATELLITE IMAGERY? Last chance for non-android GPS
« on: March 07, 2015, 04:48:51 PM »
Hey all.
New to the forum. Thanks for all the map making!!
BUT!!!  Coming from Android and Back Country Navigator, I say Long story short!! Iv been permanently forced out of my beloved Android life.
And my new dealings with regular GPS units has literally drove me to the brink of insanity!!!
So...... I prey that someone can give me some hope.
I do not mean to offend any dedicated GPS people. I truly thank you for desperately trying to keep GPS units alive.  FYI I am VERY capable with computers. (when pointed in the right direction.) In one afternoon have manged to loaded some of your topo maps on to my NUVI 2757. I bought the NUVI 2757 TODAY  It is my first dedicated GPS unit in many years. I bought it after a "little" research and seeing what you all have done on this site. I refused to believe that SATELLITE and "ORIGINAL" TOPO IMAGERY was imposible on a large screen GPS unit. BUT!!
Final Question.. (the answer to this question will literally determine wither I EVER touch a Non-Android GPS again.
Is it possible "AT ALL" to put SATELLITE or "ORIGINAL" TOPO IMAGERY on a NUVI 2757?

Boyd

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Re: Nuvi 2757 SATELLITE IMAGERY? Last chance for non-android GPS
« Reply #1 on: March 08, 2015, 04:42:28 AM »
The short answer is clearly "no". The nuvi can only display vector imagery - maps that consist of geometric objects (lines, points and polygons). Satellite imagery is raster imagery, maps that consist of pixels.

But this is something that has interested me for a long time, since I would like more options to use on a big screen device in the car. So I have been doing a lot of work on methods to convert raster imagery to vector imagery. Here are a couple screenshots of my my most recent effort, taken from a Nuvi 3550. It covers the whole state of New Jersey.

My method of creating this map is very complex but here's a very brief overview. I sampled the colors of the NJ 2007 orthoimagery in a grid of points spaced 150 feet apart. I then used a unique dataset (only available for NJ) that consists of polygons representing different kinds of landcover. Using software that I wrote, I counted all the points that fell inside each of these polygons. Using complex logic, my software chooses a color for each polygon based on how many samples it contains.

The result was a map that consists only of polygons (no points or lines). Now this kind of map only seems to work on certain new models of the Nuvi. On my older devices, it just looks like a big mess. These new models actually render the map as a 3d model of the earth's surface while others use a more crude 2d method. These models include the Nuv 3xxx series (glass screen multi-touch devices). It also works on my Dezl 760. Not sure about other newer models.

Since the map is so specialized, I have decided not to offer it for download. So, at least for now, it's just a personal project.  :)

Anyway, this doesn't really help you much, sorry. The only way to display something resembling satellite imagery on the nuvi is to convert it to vector imagery. This is sort of like fitting a square peg into a round hole.

If you really want satellite imagery on a Garmin device, take a look at the Montana and Monterra. They can natively display it, and you can purchase unlimited downloads for $30. You will be limited to a 4" screen however.




« Last Edit: March 08, 2015, 04:45:08 AM by Boyd »

Boyd

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Re: Nuvi 2757 SATELLITE IMAGERY? Last chance for non-android GPS
« Reply #2 on: March 08, 2015, 08:13:05 AM »
Also… what do you mean by "original topo"? Do you want scans of paper USGS topo maps? that would also be raster imagery and not compatible with the Nuvi. I have a map that was created to resemble the appearance of the USGS topos however. Am working on an update but it isn't ready yet. It will work fine on the Nuvi. You can download the 2012 version here:

http://www.gpsfiledepot.com/maps/view/294/

Most of the maps on this site will work on the Nuvi, but they may not look very good and some of the features will not display properly. The default display of topo maps on the Nuvi is pretty bad, but the mapmaker can optimize them to look better. Unfortunately, I am not aware of anyone other than myself who is actually doing this.
« Last Edit: March 08, 2015, 11:36:45 AM by Boyd »

jubatus

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Re: Nuvi 2757 SATELLITE IMAGERY? Last chance for non-android GPS
« Reply #3 on: March 08, 2015, 02:37:11 PM »
Much appreciated! That is some AMAZING work your doing there. I do understand Vector and Raster coming from a graphic design background. I really appreciate such a thorough answer from such a knowledgeable member so as to put the question to rest. Don't want false hope. again thanks. and hope your work continues.