Welcome, Guest. Please login or register.

Login with username, password and session length
Forums Search:  


Author Topic: Maximum size for Custom Map tiles -- 1 megapixel or 1024x1024?  (Read 3428 times)

hwstock

  • Mapper
  • ***
  • Posts: 54
  • Karma: 0
    • View Profile
I see inconsistent advice on this front.

Garmin website claims 1 megapiaxel for x*y is the limit, others claim the tiles must be square 1024*1024. Garmin gives example like 512*2048, which leavels we to wonder in non-power-of-2 values are usable (e.g. 666*1500).

And while we are at it... do you know a good reference for making custom maps with several tiles in one kmz, as in Goggle Earth?  Thanks
« Last Edit: July 10, 2013, 12:15:51 PM by hwstock »

Boyd

  • Expert Advisor
  • *****
  • Posts: 3843
  • Karma: 43
    • View Profile
Re: Maximum size for Custom Map tiles -- 1 megapixel or 1024x1024?
« Reply #1 on: July 10, 2013, 04:49:15 PM »
I have made many maps at 1024x1024, including the ones here. http://www.gpsfiledepot.com/maps/byuser/282/ They work fine. Never felt the need to use odd sizes like 666x1500 (and that sounds evil anyway)  ;)

Several ways to automate the process of multi-tile maps. Check out g-raster, the author is a member here: http://moagu.com/?page_id=155

Also mapc2mapc which is interesting, because you can individually enable/disable tiles which helps with irregularly shaped maps: http://www.the-thorns.org.uk/mapping/

I played around with this a long time ago, but have never seriously used either program. I made all my custom maps with GlobalMapper. But that's a rather expensive GIS package.

dbperry

  • Mapper
  • ***
  • Posts: 57
  • Karma: 3
    • View Profile
Re: Maximum size for Custom Map tiles -- 1 megapixel or 1024x1024?
« Reply #2 on: July 10, 2013, 08:25:31 PM »
In all of my KMZ files, I couldn't find a real good example of an image that went to 1 megapixel with one side not being 1024 pixels. This was the best I can find - the image is 700 * 1106, which is only 774,200 pixels. But it definitely proves that you are not constrained by 1024 pixels in either dimension of the image. I usually am just lazy and resize the images I am working with so that the long side of the image is 1024 pixels - then I know I am within the Garmin 1 megapixel limit.

http://www.gpsfiledepot.com/maps/view/629/

So, yes, you can do any combination of pixel dimensions as long as the overall pixels are less than 1,048,576 pixels (which is 1 megapixel, 1024^2). So your example of 666 * 1500 would work, but you are leaving some pixels on the table - you could do 699 * 1500 and it would also work.

I use mapc2mapc for producing tiled KMZ maps.

Instead of restating it here, see also my discussion on the resolution of tiles for KMZ maps:
http://forums.groundspeak.com/GC/index.php?showtopic=307548


Dave

hwstock

  • Mapper
  • ***
  • Posts: 54
  • Karma: 0
    • View Profile
Re: Maximum size for Custom Map tiles -- 1 megapixel or 1024x1024?
« Reply #3 on: July 11, 2013, 12:08:28 PM »
I ended up just registering graster for $5!

 

anything