Gmap4 = Share enhanced Google maps

[Jelf]

(I checked in with the admin first and got the OK to post.)

OK, you are back home after a trip and now you want to post in a forum/blog/website somewhere and show people your GPS track and some waypoints you collected. You can do that with Gmap4 in three easy steps:

1. Put your GPS file online almost anywhere
2. Make a Gmap4 URL that points to your file
3. Paste that URL into your forum/blog/website post

Make your Gmap4 URL like so:
http://www.mappingsupport.com/p/gmap4.php?q=full_url_to_your_file

Here is an example showing a GPS track along roads through part of the Alps:
http://www.mappingsupport.com/p/gma...t/uploads/2011/05/RoutedeGrandeAlp-Stage3.kml

Now lets fly over the above map in 3D.
1. Click Terrain in the upper right corner and select Earth from the dropdown list.
2. In the window that appears, either click “Continue” or install the Google Earth browser plugin.
3. If you clicked “Continue” then the map will shift into 3D mode.
You can fly by doing right-click-hold and shift-left-click-drag. You can also use the controls in the upper left corner.

Wait - there is more. The next time you are writing about a particular place, here is how you can include a URL that will open a map and show a symbol at that place. Assume you want to say something about Liyn Cwn bychan in Wales. If you start Gmap4 without any URL parameters, then you get a world map:
http://www.mappingsupport.com/p/gmap4.php
Click Menu ==> Search. Gmap4 can search on addresses, place names and any reasonable way to write a latitude longitude.
Enter Liyn Cwn bychan and then click Search.
Tweak the map as you prefer (map type, zoom, pan).
Click Menu ==> Show map URL and copy that URL.
(optional) Delete the URL parameters that are set to their default values.
At the end of the URL add &symbol=pgs

Here is the finished URL:
http://www.mappingsupport.com/p/gmap4.php?ll=52.861512,-4.020774&t=h&z=12&symbol=pgs

Gmap4 is a browser app. There is nothing to download, nothing to install. It will run in the browser on most smart phones, desktops and anything in between. However, since Gmap4 is based on the Google map application program interface (API), the browser has to be online. Also, Gmap4 cannot (yet) read files from your local harddrive. If you do not have your own webspace for putting files on line, then both dropbox and Google sites provide free hosting. The Gmap4 Help file has step-by-step instructions for using Google sites.

Gmap4 cannot work offline and also does not have any way to let you download maps for offline use - although you can print maps.

Another think you can do is click the map to make tracks, routes and waypoints. You can download and save your work as a GPX file.

Here are some Europe sites using Gmap4:
United Kingdom - http://www.wowzers.webspace.virginmedia.com/walks.htm
Italy - http://patotato.it
Netherlands - http://www.dehulst.nl/ci-bin/gc_sub.pl?stylesheet=/XSL/stage0.xsl

If you are interested in maps of the USA, then Gmap4 can display three different sets of detailed topographic maps at a 1:24,000 scale. Here is a very high resolution (“t4 Topo High”) map for part of Yosemite National Park in California:
http://www.mappingsupport.com/p/gmap4.php?ll=37.74481,-119.582268&t=t4&z=14

The “t2 My Topo” maps include 1:50,000 scale topographic maps for Canada.

There is no cost for using Gmap4 for non-commercial use although donations are always gratefully accepted.

You can find out about the other features that I have not mentioned by visiting the Gmap4 homepage which has a new user FAQ, examples, a detailed pdf Help file, a links page with more examples, beta code with a phone ‘skin’ and a bit about me.

Gmap4 homepage: http://www.mappingsupport.com/p/gmap4.html
Mapping Support homepage: http://www.mappingsupport.com

Enjoy!

Joseph, the Gmap4 guy
Redmond, Washington State, USA

 

[SimonD]

Joseph what about Africa and Asia? Maybe you should talk to Tracks4Africa?

 

[SpinDrift]

When I clicked on the Alps example link I could scroll down to Africa and there was even street level detail for some towns - I tried Smara, Marrakech and Cape Town, so I would imagine that the track overlay would work for in Africa and Asia as well.

 

[SpinDrift]

Joseph,

first of all well done on the program. It looks good and will prove useful.

I know that the track files are to be uploaded to a server of our choice on the internet and the program then calls the data from there to creat the overlay. What happens to the data once the program is run? Is it copied somewhere else? Do we retain full control over that data? For example, if we delete the file we upload is it deleted from the internet or is it also cached somewhere else?

 

[Jelf]

Thanks for the kind words.

Yes, you can display GPS data for anywhere in the world. The following link will start Gmap4 and display a file with symbols at various tourist spots in Africa. Click a symbol for more information. I found this file with a Google search.
http://www.mappingsupport.com/p/gmap4.p ... africa.kmz

Most programs that can display GPS data (GPX, KML, etc files) require you to first upload your file to their server. Once you do that there is a risk that you no longer have exclusive control over your own data.

Gmap4 is different. Because you get to pick where you put your data online, you retain exclusive control over your data. If you take your data file offline, then Gmap4 will not display your map. Gmap4 only displays maps for data files that are currently online. Also, the data file must be on a publicly accessible server and not on one that requires a password.

KML and KMZ files can be read directly by the Google Map API (Application Program Interface). Gmap4 does not cache those files.

However, the Google map API cannot directly read GPX or TPO files. Here is how the magic works.
Code on my server:
1. Reads GPX and TPO files
2. Converts those files to KML files
3. Temporarily hosts those KML files on my server
The map you see on your screen is coming from that temporary KML file.
Periodically those temporary KML files are deleted from my server.
If you delete the original GPX or TPO file while the temp KML file is still on my server, then Gmap4 will display an error message saying the file cannot be found.

Bottomline - One of my design goals was to give people control over their own data and only do the minimal amount of caching that was necessary in order to display certain file types.

 

[SpinDrift]

Thats great. I'll give the program a try. Many thanks.