Assistance plotting GPX data on offline aerial imagery
 

Hi,

I am trying to solve a seemingly simple problem, but am having an unreasonable amount of trouble with it, and I am hoping for your assistance.

I am riding an offroad rally in North Africa and would love to be able to plot each days route (from a GPX file) on high resolution sattelite/aerial images on my Windows laptop, but I will not have any internet access. I would love to use Google/Bing imagery, but would also be happy to use Landsat data instead.

So a few questions:
- What Windows application is suitable for this? Given that it must be able to use offline imagery data.
- Are there any recommended sources of data other than Landsat that I should be looking at? Area of interest is Morocco, Mauritania and Senegal, and a very large area (probably equivalent to 50% of Morocco to give an idea of scale).

I am also having trouble with the mechanics of getting the imagery data converted/formatted/georeferenced correctly to be displayed in the various viewer programs I've tried. Any suggestions here?

I understand these may be some basic questions, so links to guides/FAQs/tutorials are valued too.
Thanks
Ben


Just a couple of bonus bits of info:
- No need for live GPS tracking. An active GPS will never be connected, data will just come from a GPX file.
- I understand that I will have to download a huge amount of data beforehand.
- The simpler and easier the better. I just want to get an idea of the terrain along the next day's route.
- Whilst free is good, I'd happily pay an amount ($20-50) for programs/aerial data.

Also, currently TopoFusion is the leading candidate, but will require manually moving through all areas to pre-cache image data. Which I think will be too time consuming to be feasible.

OK, just a bit of a rundown of what I have done in case anyone ends up in the same situation as me. I ended up using Basecamp and Birdseye to get and display data.

The main challenge is that Birdseye is designed to load aerial images to a compatible GPS unit, not just view them in Basecamp. So there are some hurdles if you, like me, use a good old 276c.

Firstly open Basecamp and there is a Birdseye menu with an option "Download Birdseye imagery...". Good so far, but Basecamp then searches for a compatible GPS attached to the computer. If you don't have one of them you need to fool it by loading the .XML file hosted here (need to sign up to download it) into a folder named "Garmin" in the root of a USB key, so that it looks like a compatible Garmin unit. Then you can choose the Birdseye product (I used Sattelite Imagery Subscription V2).

Birdseye is a subscription service costing about $40 a year. I'd happliy pay that, but to purchase it online you MUST have a compatible GPS unit registered to you Garmin account. I don't, but you can use the demo version and a workaround. The demo version allows you to download only one aerial image (problematic, but can be fixed as described below), and will not allow you to transfer the images to a GPS (no issue for me).

Now to use the demo just click "Continue" and you can then select the area and quality you want to download. There are limits to the size of each download:
Standard quality: 5000 tiles, 57Mb, roughly 60km x 60km
High: 107Mb, 20 x 20km
Highest: 76Mb, 7km x 7km

Hit download and things get going. A single .JNX file will be downloaded, containing all the sattelite data selected. I find it takes about half an hour to download each 57Mb chunk of Standard data. Even underway you can see the data tiles pop up in Basecamp. And now you have some sattelite imagery over which you can plot routes and waypoints etc.

Now, using the demo version, if you try to download another area of sattelite imagery then Basecamp will warn you that the previous image will be deleted. This is only half true. You won't be able to see the imagery in Basecamp any more, but the actual .JNX data file will not be deleted until you quit Basecamp.

So what you need to do is as you go, or at the very least before you quit Basecamp, is to copy all the .JNX files out to another location. By default the Birdseye .JNX files are downloaded to:
%APPDATA%\Garmin\BaseCamp\JnxFiles

For me, using Windows 8.1 I found them in the "Roaming" directory. In my case this was:
C:\Users\bc\AppData\Roaming\Garmin\BaseCamp\JnxFil es

If you want to store them elsewhere, on an external drive, or a simpler path you can set up a new database in Basecamp (Google how to do that).

So now you can build up a depot of .JNX files covering the area you are interested in. Though it is very labour intensive for large areas or high quality. To then view all the images in Basecamp again takes a trick too. I copied them to a "\Garmin\Birdseye" directory on my USB key that was made to look like a Garmin GPS. Then once this is recognised in Basecamp it will show that it contains all the Birdseye data you've downloaded. This can then be copied into your Basecamp library and used as you see fit. However be warned, if you download more Birdseye images you will no longer be able to see this data in Basecamp, it will need to be reloaded.

So that is what I've learnt from extensive Googling over the last couple of days. Hopefully it is helpful to someone else one day.

Ben

Also, I used Standard quality images, and that seems to be enough to identify roads/tracks across the landscape.

Brilliant.

Seems a very nice solution.

Huge thanks for sharing this on the forum.

--Ian