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Author Topic: Best big screen GPS for custom maps  (Read 379 times)

lfsage

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Best big screen GPS for custom maps
« on: October 30, 2017, 08:34:44 AM »
Hi,

Im quite new to GPS, but are really liking its functionalities and possible applications.
Im currently using an Oregon 700 to upload custom maps of farms.  This allows me to walk a farm and know in which lot of farm I am.
Im preparing the custom maps using the GarminCustomMap plugin available for QGIS.
The Oregon 700 works ok, but I would like to have a bigger display.  Which GPS would you recommend? (It has to be compatible with Custom maps).

Thanks!

Boyd

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Re: Best big screen GPS for custom maps
« Reply #1 on: October 30, 2017, 10:45:56 AM »
Garmin has intentionally crippled their custom map format out of concerns that it could impact sales of their own products. Unless you are using a Garmin device, there is absolutely no reason to use "custom maps". But if you want to stick to that format, the largest screen Garmin devices available are the Zumo 595 and GPSMap 276cx, both have 5" screens

https://buy.garmin.com/en-US/US/p/536397#specs
https://buy.garmin.com/en-US/US/p/539722

I don't know anything about the Zumo, except that it's expensive. The 276cx has been very controversial and Garmin has alienated many long term customers due to bugs and poor performance. See this lengthy thread for example: http://advrider.com/index.php?threads/garmin-announces-the-new-gpsmap-276cx.1178312/

Regarding the limitations of the custom map format, it will only support a maximum of 600 map tiles at 1024x1024 pixels each. That is a tiny footprint and seriously limits the coverage area, especially if you want to work with high resolution imagery (such as 1 foot per pixel).

It also does not support multiple zoom levels and forces you to use jpeg files which can be inferior to tiff or png files. There are many other raster imagery formats that work across a broad variety of devices including Android and iOS apps. This gives you access to multiple zoom levels, where a different map is displayed with zoom level, allowing things like text to be readable as you zoom out. And there are no practical limits to how large these maps can be as the imagery is stored in a database.

You can get very nice large screen Android tablets for under $200 and if you want better accuracy you can use a bluetooth GPS such as the $100 Garmin GLO or even expensive receivers that can give sub-meter accuracy.

So, IMO, you should not waste any money pursuing a large screen device for Garmin Custom Maps, it will be expensive and very limited. If your Oregon doesn't meet your needs, perhaps a Montana would be good enough (4" screen)? You can get a factory refurb Montana 600 with full warranty for $300.

Otherwise, you should look at either an Android tablet or iPad with an app (there are many inexpensive ones) and possibly an external bluetooth GPS receiver. You can still use QGIS to create your maps, but you would just need to export them in a compatible format.
« Last Edit: October 30, 2017, 10:48:00 AM by Boyd »

jolly47roger

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Re: Best big screen GPS for custom maps
« Reply #2 on: October 31, 2017, 12:50:12 AM »
There is a Windows program - MAPC2MAPC that will convert your existing custom maps to various formats for Android and iPad Apps.

And there is an App called EasyTrailsGPS that says it will use the Custom Map KMZ files directly (but I have not tried it).

MojaveMan

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Re: Best big screen GPS for custom maps
« Reply #3 on: November 01, 2017, 04:46:05 AM »
So, IMO, you should not waste any money pursuing a large screen device for Garmin Custom Maps, it will be expensive and very limited.

I am a long time lurker and very infrequent poster who gets a LOT of mileage out of Garmin Custom Maps.  I find them to be very useful and honestly, my enjoyment and usage of my GPS would be very limited without them.  I think the key to understanding their limitations is key to using them effectively, and Boyd has done a pretty good job of citing those limitations.
If your need detailed custom images for small areas (like a farm) on a relatively small handheld device, Custom Maps will fit the bill.  But its important to keep in mind that the capacity of the device can be limited.  This can be circumvented by carrying multiple memory cards, but I have never found that to be necessary.
If I remember correctly, I have put 4 USGS Topo quads on my Oregon with no problem (they were 300 dpi "prints" of the official USTOPO maps) along with 4 600dpi photo images of the area I went camping.  That is some reasonably high resolution (I can easily see individual trees and the 3 foot wide trail in the photo) and covers more than a generous area for something like camping and backpacking - about 30 square miles.
The drawback is that I have to manage the files on the memory card every time I go camping to a different location.  Not a big deal to me - I move some files around on the memory card as part of my prep for the trip.  The bigger drawback, honestly, was converting the projection provided by the USGS to work on the Garmin - but when it comes to math, I'm a glutten for punishment and honestly enjoyed the process.