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Messages - Boyd

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General Discussion / Re: Create LIDAR overlay
« on: October 15, 2019, 10:24:46 AM »
LOL, nothing to "disclose" there, it's available from the National Map, just like other elevation products. If available, you'll see 1-meter DEM listed in a search.


FInding coverage areas is frustrating on their site. They often show big polygons of available data, but when you look at the downloads, only a little corner of that area is actually covered.

But I think there are large parts of the US (maybe even the majority of it?) with no high res LIDAR data available at all (neither 1/9 arc-second nor 1-meter). Fortunately, there is very good coverage of my small state of NJ, and it's more than enough to keep me busy making maps. :)

General Discussion / Re: Create LIDAR overlay
« on: October 15, 2019, 09:18:57 AM »
I'm attaching an extreme close-up of the shaded topo I posted above.indicates.

FWIW, here is an example of 1-meter LIDAR at full resolution


This view would be equivalent to the resolution of 1/3 arc-second data (although it was created by down-sampling the hi-res imagery)


The 1-meter LIDAR is especially interesting in my flat, coastal area because it reveals things you won't find on topo maps or aerial imagery, such as overgrown cellar-holes of old structures. You can see some examples in the beta version of the new software I'm writing:


General Discussion / Re: Create LIDAR overlay
« on: October 15, 2019, 09:05:59 AM »
Seems like the key to that is the disclaimer "when produced". But, really, I don't know. In the past 1/3 arc-second data was certainly not LIDAR. Maybe they are upgrading it? Regardless, 1/3 arc-second is very low resolution, about 30 feet per pixel. That will only be useful for providing a general idea of terrain at low zoom levels. It will not reveal interesting surface detail when you zoom way in.

But if that suits your needs.... nothing wrong with it. :)

General Discussion / Re: Create LIDAR overlay
« on: October 15, 2019, 08:39:50 AM »
Your math does hold, except for one thing:  I can resize the files very easily and cover much larger areas with much smaller data.

Not sure what you're saying here.... you can take 1-meter LIDAR and resample it at 100-meters per pixel. Doesn't seem much point in doing that, the whole appeal of LIDAR is the details that it reveals on the ground. If you just want low-resolution shaded terrain, then you're wasting your time with LIDAR, just use the standard 1/3 arc-second stuff.

Didn't read that link carefully, but from what I gathered the isFAR data is only for Alaska. Did not see anything indicating the 1/3 arc-second data is LIDAR-derived. This is an old dataset, available long before LIDAR. AFAIK, they are not updating it anymore (with the exception of Alaska?)

General Discussion / Re: Create LIDAR overlay
« on: October 15, 2019, 08:22:05 AM »
The data product that I use for GRASS GIS is the "1/3 arc-second DEM" in .img format.

Sorry, that is not LIDAR-based data. This is the very old DEM that (rumor has it) was originally created by painstakingly digitizing contour lines on USGS 24k topo maps. So, it's a "theoretical model" of the terrain, as opposed to LIDAR which is "imagery" that captures actual conditions on the ground. There's a huge difference here.

The USGS NED 1/9 arc-second product is derived from bare-earth LIDAR, and it represents a HUGE increase in the amound of data. For the same area, the 1/9 arc-second data will be 9x more data. I'm not familiar with the software you're using, but would assume it could handle 1/9 arc-second in .img format as well.

The 1/9 arc-second LIDAR has a nominal resolution of ~10 feet (~3 meters) per pixel, but it is now being replaced with very high resolution 1-meter LIDAR. This is the data I work with now myself. Compared to the 1/3 arc-second data you use, a map file of the same area would be about 80x larger!  8)

Anyway, it's all just DEM and the same software should work with it. The problem will be, the Garmin custom map format is so restrictive (due to the tile limit), you'll only be able to cover a tiny area with a map made from high resolution LIDAR data.

Do some quick math - we'll assume your device only supports 100 map tiles. Each tile can be no larger than 1024 x 1024 pixels (this is constant for all Garmin devices). So, let's say you make a map 10 tiles wide x 10 tiles high (total of 100 tiles). That will be a total of 10240 x 10240 pixels. And with 1-meter LIDAR, that's an area roughly 10km x 10km (a little over 6 miles x 6miles).

In the same scenario, using the lower resolution 3-meter (1/9 arc-second) LIDAR, you could cover about 19 miles x 19 miles. The only way around these limits is to create your own Birdseye imagery, which can be done with several programs (although most of them are not free). You might look at section 6 of my tutorial, although it is based on Mobile Atlas Creator. However, the information about tile limits (and getting around them) is applicable regardless of the software that you use.


General Discussion / Re: Create LIDAR overlay
« on: October 15, 2019, 03:46:12 AM »
I have been working with LIDAR data for quite some time now, starting back in 2011. These techniques are not likely to be useful for you however


This map is the end result of many years playing around with similar techniques. It was not easy to make, the result is low resolution and although it works well in Basecamp and Mapsource, it's too complex to work properly on most garmin GPS units.


This (and other lidar-based maps on my site) are more like what you want to do:


I have Garmin-compatible, downloadable versions on my other site, for example:


I'm currently building a new site for exploring LIDAR in three dimensions using WebGL.... so I'm all about working with LIDAR.  :)

But (sorry) none of this really addresses your questions. The link that Red90 posted will allow you to make very small, simplistic maps, and it might be a good place to start, but is not really going to do what you want on a large scale. It is limited to making maps that are only 1024x1024 pixels. The unfortunate truth is, Garmin doesn't want you to make big maps like this, because they could compete with their own products.

What you want is called "raster imagery" - maps that are created from pictures of some sort, such as aerial imagery, scanned paper maps, etc. Here's a related thread that discusses some of the techniques and software.


Basically, you need some software that can read the LIDAR data and render it in the style you want. I use GlobalMapper, which is rather expensive. But qGIS is free and can do many of the same things. There are some other programs in the thread above that are more user-friendly (although less versatile).

After you have created the raster imagery, it will need to be converted to .kmz map tiles that are no larger than 1024x1024 pixels each. Different Garmin devices have different limits for how many of these you can use. My Montana can use a maximum of 500. There's some confusion about the 66 series since it's new. Was just discussing this with someone who heard that it can only use 100 tiles at a time, but you can have an unlimited number of maps like this. No confirmation as to whether that is true.

But regardless, it's a very limited format that's inferior to Birdseye in many ways. There's software that will allow you to create your own Birdseye imagery however, but it gets complicated. You need to have an active Birdseye subscription for this to work (which I think is already included with your device) and then you need to jump through a bunch of hoops to trick the GPS into thinking your map is "real" Birdseye.

I don't have the time to get into all the details, sorry. But will try to answer specific questions once you get started.

Map Making Support / Re: Mac installation automation/options
« on: October 10, 2019, 07:38:17 AM »
Last time I looked into it, creating Mac installers was not simple and required special software. I can only imagine that this has gotten worse as Apple continues locking down the Mac. The default settings won't allow for installation of any software not approved by Apple.

As for the TYP questions, I don't really know. But how big are your maps? Considering the speed of typical internet connections, wouldn't it just be simpler to create separate versions? That also makes it easier for the user.

Another option might be have them download the free TYPchanger program. It's dead easy to use, but some non-technical people might still be put off by this. http://www.javawa.nl/typchanger_en.html

BTW, everyone should be using GMAP files for windows now too, since the new version of Basecamp/MapInstall doesn't work with registry maps anymore. The tutorials on this site really should be updated to reflect this new reality.

Using The Maps/Garmin Software / Re: Can't see installed map in Basecamp
« on: October 08, 2019, 03:34:55 AM »
Great! If Basecamp was running when you installed the maps, then they probably wouldn't show until you quit and started again.

Cool!  8)

SD cards can and do fail - I've had it happen to me more than once. And a 2gb card is certainly an antique. So you might try a new card (do NOT get a 64gb card). Another possibility is that the contacts are corroded or damaged on the GPS, so you should look carefully at these.

A possible source of problems when using the Mac is the invisible MacOS files that are created. For example, if you copy a map to the card, then delete it on a Mac, it is not actually deleted, it's just moved to an invisible "trash" folder.

Try the free Javawa Device Manager program, it will ask if you want to delete these hidden files and also check for a variety of other problems.


There's also this small program from the same author, just for removing hidden files


The problems you describe don't sound like a hardware issue with the GPS.

For protected Garmin maps, there should be three files. If the map file is named gmapsupp.img there should also be a file named gmapsupp.unl and gmapsupp.gma. If those two files are missing, the map won't work. But you should see an error message such as "can't unlock maps".

Maps should always work from internal memory. Try downloading another map as a test.
If this works, then perhaps you did something to corrupt the other maps that don't work?

[edit] I may have give the wrong impression above. 3rd party maps should always work in internal memory. Official Garmin maps in download format should also work. However, if you purchased a Garmin memory card with a pre-installed map, then that map will ONLY WORK ON THE ORIGINAL CARD. It will not work in internal memory.

Are talking about a "real" Garmin map? Those should never be removed from a card, they are copy protected. Theoretically you can remove the map and put it back on the same card, but various things might have gone wrong there. And that map will definitely not work on another card.

Also, on the Mac, be sure that your card is formatted as windows FAT-32.

Try copying your maps to internal memory on the GPS and see if they work. If so, then there problem has to do with the card.

Using The Maps/Garmin Software / Re: Can't see installed map in Basecamp
« on: October 07, 2019, 04:11:12 AM »
I'd say that either you did something wrong or else there is a problem with the map you installed. Try installing a different map and see what happens. There's a problem with the Windows version of Basecamp, but AFAIK it does not affect the Mac version.

On the Mac, if everything is OK with the map, when you double-click the file then MapManager should open and ask if you want to install the map. It appears that this did not happen. If you want to try a quick test, install the Mac version of my own map here: https://boydsmaps.com/boyds-map-of-new-jersey-2018/

I know that this works properly, and it includes detailed instructions.

For starters, you are in full-screen mode and the menus are not shown there. Either exit full-screen mode, or just point your mouse at the top of the screen to show the menus. You will then see the Maps menu.

If you want a "maps button", use the View > Customize Toolbar menu and drag "Currently displayed map" to the toolbar.

Map Making Support / Re: Making new map from custom kmz maps and tracks
« on: October 02, 2019, 03:01:25 AM »
Alternative for what? If you want to use Garmin-format maps (.img files) and manage Garmin products like Birdseye on the Mac, then no. If you just want to work with tracks, waypoints and routes, then any program that can read/write .gpx files should do it.

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