Thread: Working with Ozi and Google Maps (or how to get lost scientifically)

Hi,
With a Tasmanian MySwag get together this coming weekend, and not being able to get away till Friday, it will probably be a highway run either up the East Coast, or up through the Midlands Highway and across through Conara.



These roads pass either side of some interesting country, some quite rugged, and the thought occurred to me “Why don’t we explore the bits we usually pass around.

Now if we had wings, we could go



but failing that, what is in there, and how can we get there?

The Exercise:

Travel from St Helens to Hobart by the most direct route but avoiding main roads where possible.

The method:

I tried putting a straight line between the two points in both Google Maps (and Garmin Base Camp) and adjusting the route chosen by the program inwards towards the drawn line, but kept getting a huge mess on the map as the program tried desperately to keep me on main roads, like a good tourist should.

It would have been possible in Ozi to quickly trace a route out on a 1:250,000 map, but that would have been useless on Forestry tracks, and getting down to 1:25,000 was impossibly detailed and I kept getting lost.

I needed to break it down into smaller steps.

Starting at St Helens with a ‘tourist’ map, there was a road shown down through the hills to the Esk Highway which was a good start.

However I have been up in that area and it is a maze of roads, the tourist map doesn’t indicate any of the side roads, some of which are indistinguishable from the main through road. Yep, been there done that and got lost.

With the tourist map on Ozi, I traced a rough track to act as a guide to finding roads on a more detailed map at 1:250,000



Note the bridge at the bottom of the map at Upper Scamander, because I will use that to make some comparisons.

The country looks reasonably wild and hilly



On Google Maps, there is nothing to be seen at this scale.



There is however a wealth of information if we zoom in



How to use the versatility of Ozi and the details of Google maps to get a good idea of a route through this maze?

You will need to register with Google so that you can use Google maps to place and store information on maps that you will own.
Google Maps can import .kml files, and Ozi can import/export them as well – so we can use these together.

After exporting the rough track from Ozi as a kml file we can import it to Google maps, and zoom in near our starting point so that even minor road details are visible.


Google Maps has a nice feature that draws a line along roads in the maps data base, so zoomed in on St Helens above, it is dead easy to let the line follow your pointer down the road. Move the map with the arrow keys to avoid spoiling your track.



Just keep on leading the line down the road.





Ok, next bit is a problem. The road is not in the Google data base. We are going to have to change tactics.
Click the last point on the road to finish that track, and we will continue on using a manual drawing tool. This tool knows nothing about roads, so you will have to guide it.
The road is not shown on the map, so switch to satellite image view, zoom right in to get the detail you want, but not too much so that you lose your guide line.



Switch to the straight line drawing tool and follow the road with as much detail as you feel like you want.

We have to get from the top left of this image to the bottom right to where the marked road continues.



We are now back at the road.



Click the end of the road you have just traced.
Swap back to the line tool that follows the road and continue down to the highway near St Marys.

We now have completed the trace, but have a map with a lot of construction lines that we can delete.



Line 1 is the original direction line.

The 3 pointers are where I was checking some details

The blue line is the rough trace from the tourist map

The 3 lower lines are the traces we want to keep, so all the other items get deleted.

Now here is a little ‘Gotcha!’



The little KML in blue is the export button, the other little button exports a link that only Google Earth can use, it is of no use to Ozi at all.

So how did it all work out?

Import the kml file into Ozi



Remember the place we lost the road? Here is a bit of the 1:25,000 map with out and with the kml file imported over it.



It has joined the missing bits of road nicely, and follows the roads pretty well exactly at that scale.

On my 1:100,000 the road was not shown at all



Now the trace shows it nicely, and I am confident it is accurate.



OK, I’m confident I can find my way through that little maze to the next highway, now it is just a matter of doing the same for the rest of the way back to Hobart.
I will have an accurate trace in Ozi, that I can view in 1:250k, 1:100k or 1:25k.
What could be better?

But wait! There is more.

Ozi can export the kml file as a gpx file (gps exchange file)



and this should be able to be imported via Base Camp to the Garmin which takes up much less room in the vehicle.
I have yet to try this, and it will be the subject of another posting.

cheers

Hi austastar,

your google routing technique is very cool. thanks for sharing.

cheers
Paul