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Creating NOAA charts for Garmin GPSMAP 78

Started by danpmaloney, April 26, 2011, 05:56:43 PM

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danpmaloney

I am thinking about buying a Garmin GPSMAP 78.  Does anyone know can you load the free NOAA charts onto this unit.   If you can is what you load into the GPS a chart in which you can see your boats position on the chart or is it strickly a digital map?

I saw on the Garmin website there is a product called Garmin Custom Maps, once again does that create a chart that you can see your boats position or does it create just a digitial map?

Thanks,
Dan

maps4gps

About 1-1/2 years ago I did this on my OR300.

Les offers g-raster http://moagu.com/?page_id=155 which will make this fairly easy do to.

Garmin's Custom Maps is method of displaying raster/image data, rather than a product.

The .kmz file it displays on the GPSr is geo-referenced; the GPSrs current location will display as it does for a vector mapset - unless you pan it elsewheres.

The major limitation with Garmin's Custom Map format is it is limited to 100 tiles, each no larger than 1024 by 1024 pixels.  The larger NOAA charts will require more than one file; however, the total limit is still 100 tiles, so you must change the file extension so the total tile count in files with a .kmz extension is 100 or less - the name change usually requires connecting the GPSr to a computer or perhaps Ipod.  With g-raster you can change the pixel resolution to a larger size (less detail) so a larger chart could fit withing the 100 tile limit. 
Another limitation is the 'Custom Map' (all files with a .kmz extension) can only be enable/disable as a unit.  This might be an issue if you intended/need to have charts at different scales for an area.

Boyd

Quote from: maps4gps on April 26, 2011, 07:55:20 PMThe major limitation with Garmin's Custom Map format is it is limited to 100 tiles

In Garmin's forums I just read that the new beta software now permits 200 tiles. It may only be for the Oregon x50 and GPSMap 62 series however. Have been meaning to check and see if this is true...

LIHIKER

Quote from: Boyd on April 27, 2011, 05:38:50 AM
Quote from: maps4gps on April 26, 2011, 07:55:20 PMThe major limitation with Garmin's Custom Map format is it is limited to 100 tiles

In Garmin's forums I just read that the new beta software now permits 200 tiles. It may only be for the Oregon x50 and GPSMap 62 series however. Have been meaning to check and see if this is true...

i read that to . All the beta comments that I read, whether be x50, x00 or 68s, does not say it increased in the Kmz files to 200. The only increase in tiles I see in the Beta releases are the JNX files to 250 tiles. This includes x00 series too.

Boyd

Yeah, the release notes do not mention this. But it wouldn't be the first time Garmin added undocumented changes to a firmware release.  ;)

This is what I saw, which is third-hand info so it may be wrong: https://forums.garmin.com/showpost.php?p=87405&postcount=8

LIHIKER

Quote from: Boyd on April 27, 2011, 01:40:28 PM
Yeah, the release notes do not mention this. But it wouldn't be the first time Garmin added undocumented changes to a firmware release.  ;)

This is what I saw, which is third-hand info so it may be wrong: https://forums.garmin.com/showpost.php?p=87405&postcount=8

The only way is to put in a kmz file that contains more than 100 tiles -- in which I did.  Sorry to say, for x00 units  that the Kmz file is still limited to 100 tiles. I got a screen saying that I pass the limit and it will not be displayed.  :'(

danpmaloney

Thanks for all the information.  I now think it is worth the time to try and do this.

Along these lines how would a Garmin BlueChart G2 such as the HUS039R-US g2 compare with NOAA charts that I would convert.  Would the Garmin BlueChart be a better quality (ore detail, clearer picture)?    Is it worth spending the $160 or can I get the same thing from the free maps?


Boyd

The area that can be mapped with the "custom maps" feature will be very small. Not familiar with nautical charts, but I have made a number of custom maps from USGS 24k topo's and posted them here. Due to the 100 tile limit, when using a reasonable resolution that allows you to see all the map detail, I could only cover an area about 20 miles x 20 miles.

I suspect you will find something similar with the NOAA charts. You can only have one map of this type on your GPS and would have to physically swap memory cards to use a different one.

Boyd

I will never be convinced that the 100 tile custom map limit is anything other than marketing. Garmin feels it would be against their best interest for you to make maps that might replace their own products. It is what it is, and I don't get too upset about it.

But it surely isn't a technical limitation. I have also run OziExplorer CE on a number of units including a Triton 1500, Roadmate and iPAQ. Using their ozfx3 file format you can cover very large areas, and their mapmerge utility lets you combine them into huge multi-gigabyte raster images. Map rendering is fast and it is viewable through a really wide range of zoom levels (more than you even need).

So, clearly, it CAN be done. Garmin just doesn't want to make this kind of functionality available.