New User Frequently Asked Questions (FAQ)

February 24, 2017

Question: Can I use Gmap4 for a commercial purpose?
Answer: No. Gmap4 can be used for any educational or non-commercial purpose.

Question: How do I download the Gmap4 program?
Answer: You do not need to download anything in order to use Gmap4. The Gmap4 program runs in your browser. This means that there is nothing for you to download. Also, you do not have to install anything on your computer in order to use Gmap4.

Question: Is there a Quick Start guide for Gmap4?
Answer: Yes. Please go to the Gmap4 help page and download the pdf file 'Quick Start'.

Question: How do I start Gmap4?
Answer: You start Gmap4 by putting a link into your browser address bar. It is just that easy.
This link displays the default map of the world:

Question: How do I make a Gmap4 link?
Answer: A Gmap4 link has 2 parts:

Part 1 (required):
This first part of the link is the path to the Gmap4 code which is hosted on the MappingSupport server.
If you just enter this required part of the link into your browser bar, then you will see a map of the world.

Part 2 (optional): One or more link parameters. The purpose of link parameters is to control the initial map you see on your screen. By using link parameters you can control things like the initial zoom amount, initial map center, whether your location is shown, whether a GPS-related data file is displayed and more.

Question: How can I easily and quickly learn more about using link parameters with Gmap4?
Answer: Take a look at the examples and notice how each link is built. For more information about the link parameters that Gmap4 understands please go to the Gmap4 help page and download the pdf file 'Link Parameters'.

Question: Can I use Gmap4 on my iPhone, iPad, Android or other mobile device?
Answer: Yes and you do not need to download or install anything. Gmap4 is a web application that runs in most modern browsers. Gmap4 does not care whether the browser is on your desktop, laptop, notebook, tablet, cell phone or other mobile device. However, the browser must be online to the internet in order to start Gmap4. Want a fast way to start Gmap4? Just add one or more Gmap4 links as bookmarks in your browser.

Question: Does Gmap4 work when my iPhone, iPad, Android or other mobile device is offline?
Answer: Yes. However, you first need to (1) start Gmap4 when your device is online and (2) pan the map over the area you want to view offline. For more information about using Gmap4 offline please go to the Gmap4 help page and download the pdf file 'How To Use Gmap4 Offline'.

Question: I am trying to use Gmap4 on my cell phone (or tablet) and it is very slow or freezes. What can I try to fix this?
Answer: Your phone might not have enough free memory. Try closing all the open apps and then restart Gmap4. If you are online via a cell tower then it is also possible that the cell tower is swamped with users.

Question: How do I make the scale at the bottom of the screen show feet and miles instead of metric units?
Answer: Click the scale symbol.

Question: How can I share a map that shows a particular location with someone else?
Answer: You can easily get a Gmap4 link that will reproduce the same map you see on your screen.
1. Simply use zoom/pan or Menu==>Search to find the area you want to see when the map opens.
2. Click the button in the upper right corner and select "h - Aerial Google hybrid" or one of the other choices. Also adjust the zoom to your liking (mouse wheel or sliding control in upper left corner).
3. Click Menu ==> "Link to this map". The link that is displayed will reproduce the same map you see on your screen.
These Gmap4 links can be used in forum posts, emails, blogs, websites, etc.

Question: How do I see the coordinates for a spot on the map?
Answer: Desktop/laptop users: Right click the map anywhere. A popup will appear with coordinates in various formats. That popup includes buttons for making a Gmap4 link and also getting turn-by-turn driving directions.
Mobile users: To do a simulated right click:
1. Tap the ">" symbol at the left edge of the screen
2. Drag the crosshair that appears
3. Tap the crosshair and the rightclick popup will appear
To remove this crosshair from the map, tap "<".

Question: How do I search on coordinates?
Answer: Do Menu ==> Search. Enter the coordinates (WGS84 datum) in the search bar at the top of the map and then choose one of the three actions to the right. You can search on latitude longitude, UTM, USNG or MGRS coordinates. Most reasonable ways to write the coordinates will work. Latitude longitude can be written as decimal degrees, degrees decimal minutes or degrees minutes seconds.

Question: How do I change the format of the coordinates that are displayed in a corner of the map?
Answer: To select the coordinate format you prefer do Menu ==> "UTM - USNG - LatLng" and pick the coordinate format you want. If you select UTM or USNG or MGRS then a grid with labels is displayed.

Question: What Gmap4 features support USNG (U.S. National Grid) coordinates?
Answer: For a list of Gmap4 features supporting USNG please go to the Gmap4 help page and download the pdf file "USNG and MGRS Coordinates".

Question: How do I use the GPS in my smartphone or tablet to display my location?
Answer: Do Menu ==> "My location" and your position is displayed by a red circle that will automatically follow you as you move. If you touch the location symbol (red circle) then your cooridnates are displayed using the coordinate format you selected. The default format is latitude longitude expressed in decimal degrees.

Question: I tried the 'My location' feature but it did not work at all. What am I doing wrong?
Answer: First, look at your phone's settings and make sure you have location services turned on. Second, your phone/tablet can use both GPS satellites and cell towers to find your location. However, before your phone can use data from the GPS satellites, your phone must first have a current "almanac" containing a forecast for where each satellite can be found in the sky. Go someplace where your phone has a signal from a cell tower and then try the 'My location' feature again. Your phone will likely download a fresh almanac from the cell tower and then the 'My location' feature will work. Sometimes this might take a few minutes. A fresh almanac should be good for 2 to 4 weeks.

Question: I tried the 'My location' feature but it did a poor job of finding me on the map. Why is that?
Answer: For the GPS to work best you need a good view of the sky. Also, the GPS in your smartphone or tablet might only be accurate to about 50 feet! For more information about GPS accuracy of mobile devices please go to the Gmap4 help page and download the pdf file "Using An Open Map" and read the section "Tips for mobile users and the 'My location' feature".

Question: Can Gmap4 display contour lines on top of the aerials?
Answer: Yes. Open the menu that lets you change basemaps and go the "Overlay" section. (Mobile users scroll down.) Click "USA_contour_lines". Do it again to turn that data overlay off. Also, you have to be zoomed in so that the scale at the bottom of the map says either 500 feet or 200 feet before the contour lines appear. (Click the scale symbol to change it from meters to feet.) This overlay will display on top of any basemap.

Question: How do I make a Gmap4 link that will show contour lines on top of the aerials when the map opens?
Answer: Use this 't' parameter in your Gmap4 link: t=h,USA_contour_lines
For example:,-91.368034&z=16&t=h,USA_contour_lines

Question: How do I make a Gmap4 link that will only show contour lines and not show any basemap when the map opens?
Answer: Use this 't' parameter in your Gmap4 link: t=USA_contour_lines
For example:,-91.368034&z=16&t=USA_contour_lines
Note that when the map opens the basemap is set to "All white basemap".

Question: How do I display a GPX (or KML or KMZ or TPO) file with Gmap4?
Answer: You first have to put your file online. Then copy the link that points to your file and paste it over the underline in this Gmap4 link:
Then copy the entire Gmap4 link, paste it into a browser address bar and hit enter.

Question: I do not have my own website. Where can I put my file online for free?
Answer: I use Google Sites. It is free, easy and it works. For step-by-step instructions please go to the Gmap4 help page and download the pdf file 'Working With Files'.

Question: Can one map display multiple files?
Answer: Gmap4 can display a maximum of five KML and/or KMZ files. For more information please go to the Gmap4 help page, download the pdf file 'Delimited Data' and search that file on "KMZ".

Question: Can Gmap4 read files from my local hard drive?
Answer: No. You must place your data file online in order to display it with Gmap4. You can use the free Google Sites to place your files online. See the above question and answer.

Question: Why does Gmap4 display three different sets of topographic maps for the USA?
Answer: The "t4 CalTopo Hi-res" maps are provided by and are higher resolution than online topographic maps provided by most other sources. The "t2 MyTopo" maps (medium resolution) are still provided since they include the updated information that was added to the maps by the U.S. Forest Service. The "t6 Topo ESRI" maps (medium resolution) are nice at zoom level 12 which covers a fairly large area. To see the zoom level, rightclick the map. (Mobile users: Touch Menu ==> "Link to this map" and look at the value for the 'z' parameter.)

Question: I tried to look at the topographic maps labeled "t4 CalTopo Hi-res" and only got a blank screen. Why?
Answer: These high resolution topographic maps only cover the USA. For more information on these new maps, please please go to the Gmap4 help page and download the pdf file titled 'Overview'.

Question: I read somewhere that Gmap4 does not have any ads. Why are there ad buttons on the screen when I look at the "t2 MyTopo" maps?
Answer: In 2011 the MyTopo Company was purchased by the Trimble Company. In late 2011 Trimble issued new Terms Of Service. Displaying those ad buttons is the 'price' that Trimble charges in order for Gmap4 to continue displaying the MyTopo topographic maps at no cost.

Question: What is the easiest way to make a custom map with Gmap4?
Answer: By using the following steps the data for your custom map is saved right in the Gmap4 link. You do not need any data file at all! Think of this as a map-in-a-link.
1. Click Menu ==> "Draw and Save"
2. Select one of the options for making a line or waypoints or both at once. Click Continue.
3. Start clicking the map. If you are making waypoints then you can rightclick any red paddle and edit its name and description as needed.
4. Rightclick any symbol (mobile users: tap any symbol then select "Display action menu") and select "Gmap4 link - No description" or "Gmap4 link - With description". Notice that the "markers" parameter in the Gmap4 link contains your custom data.
5. Paste that Gmap4 link into a browser address bar, hit enter and your custom map appears on the screen.
Optional: You can improve your map-in-a-link by editing the link to change line color, line width and various other things. For more information about this feature please go to the Gmap4 help page and download the pdf file 'Delimited Data' and search it for 'map-in-a-link'.

Question: How do I make a GPX file and save it?
Answer: 1. Click Menu ==> "Draw and Save".
2. Decide if you want each map click to make a waypoint and a routepoint, or just a routepoint, or just a waypoint. (To change your decision - and also to make trackpoints - rightclick the last point you added to the map, select 'Edit' and adjust the 3 checkboxes at the top of the Edit popup.)
3. Click the map to make your points. Each point is draggable.
4. Rightclick (mobile users: tap any symbol then select "Display action menu") any waypoints (red paddle) you made, select 'Edit' and add a meaningful name and maybe a comment.
5. Rightclick any symbol and select "Download GPX file". Another option lets you simply display the GPX file at any time.
Note: If you are using a smartphone or other mobile device then select "Display GPX file". Copy the file, paste it into an email and send it to yourself.

Question: How do I display GIS data?
Answer: One option is to make a Gmap4 link that includes parameters that specify the GIS information that you want to view. The other option is to make a text file that specifies the GIS information that you want to view, put that text file online and then make a Gmap4 link that points to that text file.

Question: How do I know if the map I am looking at includes any GIS data?
Answer: There are two buttons on each map. One button says "Menu" and the other button displays the name of the current basemap. Click the basemap button. On a laptop/desktop two dropdown menus will open. The one on the left shows the GIS overlay layers that can be turned on/off by clicking them. On a cell phone or other mobile device you need to scroll down to see the "Overlay" section.

Question: I am looking at a map that has a GIS overlay turned on. Can I get more information about the GIS data that I see on the map?
Answer: Yes. If you click a GIS symbol then a popup will usually be displayed that shows you all the information ("attributes") that the GIS server has for the thing that you clicked. Some GIS servers will take a few seconds to respond. You can only display data for the GIS overlay layer that is 'on top'. To find out which layer is on top, click the basemap button. Overlay layers that are 'on' have a number in front of them. The highest numbered layer is 'on top'.

Question: How do I get more information about Gmap4's ability to display data that is hosted on GIS servers?
Answer: Please see the GIS Viewer page. Also, at the bottom of that page are two links to more information about Gmap4's ability to display GIS data.

Question: Can I 'save' the map I see on my screen?
Answer: No and yes.
No, you cannot 'save' that map in the normal way that you save a file.
Yes, you can save a Gmap4 link that will reproduce the same map view that you see on your screen. Click Menu ==> Link to this map. Notice the various link parameters. If you copy that link and paste it into a new browser bar, then you will see the same map on your screen. You can email that link, post it in a forum or put it on a website and whoever clicks that link will see the same map on their screen.

Question: How do I print maps?
Answer: Printing is handled by your browser. The Gmap4 code is not involved in printing. Use Firefox or possibly Internet Explorer. Make the map look the way you want it to look and then in the Firefox menu bar click File ==> Print preview. Use the controls that appear at the top of the screen to (1) select landscape orientation and (2) adjust the scale so the map nice fits the screen. You are then ready to print.

Question: I am using Firefox. Why is Gmap4 sometimes very slow?
Answer: The reason might be due to the Firefox browser not correctly reusing space in its cache. There are two things you can do.
First, make sure you are using the latest version of Firefox. They might have fixed this problem.
Second, clear the Firefox cache by doing:
Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

Question: Can I put Gmap4 links on my Facebook page?
Answer: Yes.
Somehow or another you found out about Gmap4. If you enjoy using it, perhaps some of your friends would enjoy using it also. With that in mind, I have a favor to ask of you. If you are on Facebook, then please consider saying something about Gmap4 on your Facebook site. And if you include a map link in your post, then that will help your friends see what Gmap4 is all about. And you can also stop by the Gmap4 facebook page and post a comment and/or give us a 'like'.

Question: Can I post Gmap4 links in forums or on websites where the user is required to pay a fee to access the forum or website?
Answer: Please do not. Doing so most likely violates section 9.1 of the following terms of service from Google: Also, since Gmap4 is intended to be free, no one should be trying to make money from it.