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Gmap4 - Enhanced Google map viewer + high resolution topo maps + more
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Joseph Elfelt
(Jelff) - F
Gmap4 - Enhanced Google map viewer + high resolution topo maps + more on 02/02/2012 21:53:03 MST Print View

There are several general purpose online map tools based on Google Maps. All of us software developers do some of the same things and we also each do some unique things. It's a big world and there is room for different solutions. Different people will tend to gravitate to different tools depending on their needs.

This post is about Gmap4 - the tool that I developed. I checked in with Ryan beforehand and got the OK to post.

Gmap4 is an enhanced Google Map viewer that can display high resolution topographic maps. These maps are based on new scans that have eye-popping quality and cover the USA except for a few states that are not quite ready yet. Here’s an example showing part of the John Muir Trail in the area of Tuolumne Meadows, California.,-119.349399&t=t4&z=14

Note that this topo map (1) is very high resolution - the paper map was scanned by the USGS at 660 pixels per inch, (2) does not have any watermarks on the map ‘tiles’ and (3) does not have any ads. At the present time, there is only one other site on the planet that is displaying these hi-res topo maps in a seamless interface.

Did I mention that you can vary the hill shading on these hi-res maps? Menu ==> Hill shading

Gmap4 also displays the medium resolution MyTopo maps and the low resolution Terraserver maps (now called Microsoft Research Maps). You can do your own quality comparison.

Gmap4 is online software that runs in your browser. There is nothing to buy, nothing to download, nothing to install. Gmap4 will run on most browsers in your phone, iPad, iPod, notebook, laptop, desktop, etc. Note that the browser does have to be online to the internet. Gmap4 is not a ‘native’ app. Instead, it is a browser app.

Q: What can you do with Gmap4 besides look at drop dead gorgeous topo maps?
A: A bunch!

I just added a trip planning feature (Menu ==> Make a map) so you can click the map to make a GPX file that you can load into many (not all) handheld GPS units. Then, when you get back from your trip you can use Gmap4 to display your GPS track.

One of the main features of Gmap4 is its ability to display data files that are hosted online almost anywhere. If you want to put your own data files online but lack your own website to host those files, then just use Google Sites. It is free, easy and it works. The Gmap4 ‘Help’ file has step-by-step instructions for uploading your files to Google Sites. Gmap4 can display GPX, KML, KMZ, TPO and Google MyPlaces files. It can also display a delimited text file format that I designed. Note that you cannot (yet) display files straight from your harddrive. You first have to put your files online.

Another key feature is the ability to share your map with others. If you click Menu ==> Show map URL, then a URL will appear in the message window. You can copy that URL and use it in a forum post, email, blog, website, etc. Whoever clicks that URL link will see the exact same map on their screen.

You can also:
* Automatically center the map on your current location (works best in mobile browsers)
* Display a UTM grid
* Get the current magnetic declination
* Search
* Get directions (the route is draggable)
* Print
* And more

There is no cost for using Gmap4 for non-commercial use. It is simply my way of ‘paying it forward’. But with that said, if you like the new high resolution topographic maps please consider making a donation (Menu ==> Donate) to help offset the hosting cost of that data. You can read more about these new topo maps in the CalTopo section of the Gmap4 ‘Help’ file.

The Gmap4 homepage has a new user FAQ, examples, a detailed pdf Help file, a links page with more examples and a bit about me.



Joseph, the Gmap4 guy

drowning in spam
(leaftye) - F

Locale: SoCal
Re: Gmap4 - Enhanced Google map viewer + high resolution topo maps + more on 02/02/2012 22:22:24 MST Print View

Thank you Joseph. Not just 5 hours ago I posted on FB that I wished I could view a particular route on Gmap4. Now I can!

Dylan Snodgrass

Locale: San Francisco, CA
Gmap4 - Enhanced Google map viewer + high resolution topo maps + more on 02/02/2012 22:25:25 MST Print View

Just checked it out. WOW very cool...

Buck Nelson
(Colter) - MLife

Locale: Alaska
Definitely check out Gmap4! on 02/05/2012 23:13:20 MST Print View

A friend pointed out this resource to me. Should be very useful to most people on this forum. The high res topo maps are awesome.

Edited by Colter on 02/11/2012 05:10:57 MST.

Buck Nelson
(Colter) - MLife

Locale: Alaska
Double post on 02/05/2012 23:13:58 MST Print View

Double post

Edited by Colter on 02/11/2012 05:10:10 MST.

christopher smead
(hamsterfish) - MLife

Locale: hamsterfish
Finally! on 02/05/2012 23:21:36 MST Print View

Wonderful. Im so happy this finally exists :). THANK YOU!

Kyle Meyer

Locale: Portland, OR
Gmap4 on 02/10/2012 17:45:06 MST Print View

I think this is really great. You've done an excellent job extending Google Maps in a useful way for the average outdoorsman. I sincerely hope, though, that since you're selling this commercially that you are paying for Google Maps Premier.

Personally, I'd love to see not obfuscate your work here, maybe even open source it, so others can benefit from what you've learned in doing this.

Joseph Elfelt
(Jelff) - F
Gmap4 guy says: Thanks for the kind words on 02/11/2012 06:43:15 MST Print View

Kyle is correct that Google's TOS (Terms Of Service) require that people be able to use Gmap4 to view maps at no charge. And, yes, anyone can do exactly that.

Here is a link for the FAQ that goes along with Google's TOS:
That FAQ contains an item titled: "Can I use the Google Maps APIs on a commercial website?" The answer to that Q describes a circumstance under which anyone can charge money for the usage of their Google map program without obtaining a premier license from Google (which starts at $10,000 per year).

Roger B
(rogerb) - MLife

Locale: Here and there
Re: Gmap4 - Enhanced Google map viewer + high resolution topo maps + more on 02/11/2012 08:13:06 MST Print View

Wow, impressive topographic information. Will this be expanded outside of the USA?

Joseph Elfelt
(Jelff) - F
Gmap4 can also display topographic maps for Canada on 02/11/2012 09:32:00 MST Print View

The medium resolution MyTopo topographic maps also cover Canada. The scale is 1:50,000. Here is a map for the area around Lake Louise, Alberta:,-116.212982&t=t2&z=13

You can use Gmap4 worldwide. However the true topographic maps only cover the USA and Canada.

Nico .
(NickB) - MLife

Locale: Los Padres National Forest
Gmap4 on 02/12/2012 11:28:18 MST Print View


Great tool! Thanks for sharing.

One question/suggestion... it looks like, at least for my area, that Gmap4 relies on the 1988 quads scans. Is it possible to instead link to the '95 or (when possible, even newer) quad series?

Otherwise, it's looks like a really neat resource.


Joseph Elfelt
(Jelff) - F
Gmap4 - thanks for kind words on 02/12/2012 14:40:40 MST Print View

Unfortunately I do not really have much control over which topo map is displayed.

Instead, other people have assembled 3 sets of topos. Those people are the ones that decided which topo scans to put in their set. All I can do is let you pick which set of maps you want to display.

Paul Cernak
(Cernak) - F

Locale: North Cascades
Wow...this is amazing. on 02/14/2012 20:13:11 MST Print View

I don't have a lot of experience with map reading programs but this seems to work amazing. Its fast AND high resolution! Thank you. If only we could get some high resolution data for Canada....

Edited by Cernak on 02/14/2012 20:16:18 MST.

Curtis B.
(rutilate) - MLife

Locale: Pacific Northwest
Re: Gmap4 - Enhanced Google map viewer + high resolution topo maps + more on 03/18/2012 17:35:17 MDT Print View

I just added a trip planning feature (Menu ==> Make a map) so you can click the map to make a GPX file that you can load into many (not all) handheld GPS units. Then, when you get back from your trip you can use Gmap4 to display your GPS track.

I'm impressed with the capability for hardcore mappers. I'm not a GPS user; I'm trying to create a map of an upcoming trip to the Wind River Range. One thing that I seem to be missing is the ability to create trails. I see how to create waypoints but how can I create cleanly marked trails such as your example of the John Muir Trail? I would like to trace a path along a trail and mark campsites and sites of interest. What am I missing? Or do people create their maps elsewhere and view/share with this tool?

Edited by rutilate on 03/18/2012 17:35:56 MDT.

Joseph Elfelt
(Jelff) - F
Gmap4 - How to make a trail map on 05/01/2012 07:01:57 MDT Print View

Curtis - Sorry it took me so long to see your post. (Is there some way to 'subscribe' to threads on this forum?)

When you use the 'Make a map' feature of Gmap4 there is a default manner in which the feature works. By default each time you click the map you get both a symbol and a line. If you only want a line, then:
1. Click the map to set the first symbol
2. Right click that symbol
3. Select 'Edit this point'
4. Uncheck the 'Waypoint' box
5. Save and close

Now continue clicking the map and you will get just a line.

Big picture: Each time you click the map that point can be a waypoint and/or trackpoint and/or routepoint. You control those 3 things with the 3 check boxes on the edit screen.

Joseph, the Gmap4 guy

Michael Ray
(topshot) - MLife

Locale: Midwest
Re: Gmap4 - How to make a trail map on 05/01/2012 07:19:09 MDT Print View

At the top of each thread, you'll see a "watch this thread" link near the right menu bar. You can see which ones you have subscribed to by "view my profile" in the said menu bar.

Joseph Elfelt
(Jelff) - F
Re: Gmap4 on 05/02/2012 07:05:09 MDT Print View

Michael - thanks
My bad for not seeing that
It was so obvious it almost bit me

Sabine Funk
(SabineFunk) - F
and also for Europe on 06/22/2012 08:59:35 MDT Print View

Hi guys,

if anyone comes to europe to hike in the alps, we have a similar thing:

Unfortunately only in german, but there's not much you have to understand...
The green button "Route zeichnen" means draw a route to get a gpx-file.

Ben R
(snowfiend131) - MLife

Locale: Western PA
Gmap 4 Printing on 06/24/2012 15:38:43 MDT Print View

Joseph - Any plans to add more advanced printing (such as printing with map detail greater than the current zoom level)? If I could print a map at the scale of zoom level 13 but with the detail of zoom level 15, I could use this to make high quality paper maps like I do with Delorme Topo USA.

Joseph Elfelt
(Jelff) - F
Gmap4 printing on 06/24/2012 15:49:39 MDT Print View

Alas, printing is controlled 100% by Google and your browser. My code has nothing at all to do with printing.

Joseph Elfelt
(Jelff) - F
Gmap4 - Easy and fast way to make a custom online topo map. No data file needed! on 03/22/2013 14:13:22 MDT Print View

Recently Gmap4 was updated to version 4.1 and now includes a unique map-in-a-link feature that is worth mentioning. Anyone can now make a custom map and save their data right in a Gmap4 link. You do not need to save your data in a separate file such as a GPX or KML file. This may be the easiest and faster way for you to make a custom online topographic map.

To try out this feature:
1. Click Menu ==> Draw and Save
2. Click the map a few times to set draggable symbols and draw a line
3. Rightclick any symbol and select “Gmap4 display long link”

You can copy the link that is displayed, paste it into a new browser address bar, hit enter and your custom map will be displayed.

This feature also works on your iPhone, iPad, android and other mobile device. Remember, Gmap4 is a browser app and your browser has to be online. After you tap the screen to set some draggable symbols then tap a symbol and select “Action Menu”. The list of actions include two different ways to save a Gmap4 link that includes your data.

More information on this map-in-a-link feature can be found in the following three places.

1. What’s new page
Note the tip about deleting the ll and z parameters from your Gmap4 link.

2. Example page
Scroll down to the section titled “Your map data saved in the Gmap4 link”. The examples range from basic to advanced and give you a quick way to see some of the kinds of maps you can make with this feature.

3. Help file
You can download the PDF file and search it (control-f) for the section titled “Make a custom map with Gmap4 and save it”.

Joseph, the Gmap4 guy
Redmond, WA

Joseph Elfelt
(Jelff) - F
Gmap4 can now display a vast amount of transparent overlays on 06/14/2013 21:00:24 MDT Print View

Some of you already know that Gmap4 is a general purpose file viewing tool for GPX, TPO, KML, KMZ and a couple of other file types.

I have posted beta version 934 (June 13th) that lets Gmap4 also be a general purpose WMS viewer. Why might you care? At last count there were approximately 1.2 bazillion WMS servers out there and this beta code can display most of that data. Specifically, you can:

* Build a Gmap4 link to display multiple layers from multiple WMS servers
* Turn transparent layers on/off one at a time or all together
* Change the stacking order of transparent layers
* Display transparent layers on top of any basemap hardcoded into Gmap4 or on top of any basemap added via WMS

As a software developer, it is always exciting to develop a feature that is first-of-its-kind. If there is any other software that lets you "click link - see WMS data", I would like to know about it.

The Gmap4 beta page has more examples and documentation showing step-by-step how to make your own Gmap4 links to display any WMS data you wish to see.

The example maps on the beta page include:
* Boundaries of federally owned land
* USA map with current weather radar
* NOAA coastal navigation charts including the most detailed charts
* Current forest fire boundaries
* Index to 1:24,000 scale topos for USA
* Index to 1:50,000 scale topos for Canada
* and more

There might be some kind of limit as to how complex(?) these maps can be. Gmap4 uses the Google map API but Google’s docs do not mention any such limit.

I would enjoy seeing any cool way you use this feature.

Also, while I am happy to answer questions please help me help you by first reading the information on the beta page. That information will answer a great many questions.

Joseph, the Gmap4 guy
Redmond, WA