# Display TOPO! tpo files with Gmap4. Free, no ads. Detailed topographic map



## Jelf (Jun 26, 2010)

Gmap4 is an enhanced Google Map viewer that can now display GPS tracks and waypoints from your *TPO files*. You can view your GPS data on high quality topographic maps provided at no charge by the MyTopo company (www.mytopo.com).

*TPO files* are produced by a number of versions of the National Geographic TOPO! software. Gmap4 also reads GPX, KML, KMZ and Google MyMap files.

Gmap4 runs entirely online. There is nothing to buy, nothing to download, nothing to install.

You do need to place your TPO or other data file online before it can be read by Gmap4. The easiest/fastest way to place a TPO file online is via Google Sites (free). Don't be shy. You will find hand-holding-step-by-step instructions in the Gmap4 Help file.

The following link produces a map from a GPX file hosted on Google Sites (TPO files work the same way):
http://www.mappingsupport.com/p/gmap4.php?q=http://sites.google.com/site/gmap4files/p/helpfile/Johnson_Ridge.gpx&t=t2

Below is a link to the Gmap4 homepage. Check out the 'Examples' and Quick Start section of the 'Help' file.
http://www.mappingsupport.com/p/gmap4.html

Enjoy,
Joseph


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## Harold (Dec 23, 2003)

That's an interesting update. Did NG finally decide to offer up the schema for their .tpo files so other programs could use them? Topo! has used that file format for years and years, but there was practically no compatibility in other programs.

Maybe has something to do with it becoming the default software for Magellan receivers?


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## Jelf (Jun 26, 2010)

No, the .tpo file format is just as secret as ever.

Fortunately the smart folks that contribute code to GPSBabel have been able to reverse-engineer a lot (not all) of the tpo file format. This applies to tpo files made with v2, v3 and v4 of the TOPO software.

Gmap4 reads your tpo file and executes GPSBabel on the Gmap4 server to convert your tpo file into a kml file. That kml file is temporarily hosted on the Gmap4 server and used to produce your map.

Joseph


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## Harold (Dec 23, 2003)

Ahhhh, clever trickery. I like it!

Keeping geographic data formats secret is prime stupidity. I could understand if you've got a fancy image format and you want to license it out for a fee or something, but even still...the best thing Garmin ever did was support the .gpx format way back when to make it easier for folks to share data. And now they support .kmz, another open format.

I think companies who maintain closed file formats are shooting themselves in the foot when they compete with successful companies who support open formats.

Look at how much geographic data is shared across multiple platforms nowadays. The map sharing thread is a great example. Folks sharing their GPS data collected from a variety of devices using a variety of tools.


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## Jelf (Jun 26, 2010)

Note that I am now recommending the use of Google Sites (free) for placing GPX, TPO, KML and KMZ files online. If you have not used Google Sites, don't be shy. Hand-holding-step-by-step instructions are included in the Gmap4 Help file.
http://www.mappingsupport.com/p/gmap4_help.pdf


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## Wherewolf (Jan 17, 2004)

*Thanks!*

I discovered Gmap4 last year and it is great!


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## Harold (Dec 23, 2003)

Yep, Wherewolf shared it here on this forum and I've since started using it. Thanks for sharing, Wherewolf.


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