Sharing A Map

This article covers the basics of sharing a map on the web and mobile app. Although the screenshots are from CalTopo, the process is the same for SARTopo. If you would like to jump ahead to a particular section, click below:

Blank, draft and saved maps

CalTopo has three basic modes of operation:

Blank maps do not yet contain any data (markers, lines and polygons), but may contain custom layers. Since the entire map state is stored in the URL, nothing is actually saved to CalTopo's server. A blank map will have a URL of /map.html, possibly with a bunch of extra information, e.g. /map.html#lI=39.4617,-106.46438&z=16&b=mbt&o=r2&n=0.52.

To share a blank map, use the Collaborate link in the left bar.

The dialog box that comes up provides a URL for the map that can given to other users in order to share the blank map.

Since the sharing URLs are often quite long, you can click on the Shorten link in the dialog to produce a shorter URL for easy sharing, e.g. /l/7GHH.

Draft or unsaved maps contain markers, lines or polygons, but have not yet been saved to CalTopo. You can still access most features, including exporting and printing, but your data will be lost as soon as you leave the page. It is important to save your map as soon as possible to prevent the loss of data.

When you add an object to your map, the Collaborate link will be replaced with a red Save this map link. A Save link will also appear in the top nav bar.

Clicking either of these links will bring up a prompt to sign in or the Save As dialog box if you are already signed in. You must either be logged in or log in prior to saving a map.

For more information on sharing, see below.

Saved maps are ones where the data has been saved to CalTopo. On a saved map, the URL is m followed by a 4-digit code that is a unique combination of letters and/or numbers, e.g. '/m/11FC`. The Collaborate link will also be visible again in the left bar.

In a style similar to other online editors such as Google Docs, changes made to a saved map are automatically synced to all other users. If you and a friend are both looking at the same map, any new lines you draw will automatically show up on your friend's computer.

Base permissions

When saving a map, you have the option to change the base permissions for the map. Base permissions designate who can view or edit your map and how they can access it.

There are four different base permissions that you can assign to a map:

  • Private maps are only visible to you. Even if someone else knows the map's URL, they will be unable to view it.
  • Secret maps cannot be viewed with the map URL only. When the map is set to Secret, you must create shareable links in order to share the map with others. You can create multiple links to give different users different levels of access to the map. These links can be shared as a link or as a QR code, which the CalTopo app can read.
  • URL maps are accessible to anyone who knows (or guesses) the 4-digit map ID in the URL. This is the default option for all maps.
  • Public maps show up on CalTopo's Shared Maps layer and are indexable by Google. Use this option for map data you want to share with the world.

Once you have saved your map, you can create shareable links in order to give other users different levels of access to your map. Click the Collaborate link in left bar. The Sharing dialog box will now open.

You can change the base permission of the map here. For example, you could change the base permission from the default URL to Secret. Please note that you cannot create links for private map; if you wish to share your map, you have to change the base permission.

In order to create shareable links, click on the + Create Password or Shareable Link link at the bottom of the dialog box.

This will open the Grant Access dialog box. Click Create A Shareable Link and select which access type you would like to create a link for from the drop down menu.

There are three different access types:

  • Read access means that another user can only view your map. They cannot edit the map. Read only links are not necessary for URL or public maps since these can be shared with read access using the map ID or URL.
  • Update access means that another user can add objects to your map, but not edit or delete your objects. They are able to modify objects they add themselves.
  • Write access means that another user can edit the map. They can add, delete and edit all objects on the map.

Once you have selected your desired access type, click OK and a unique shareable link will be generated for that access type and appear under Additional Access in the Sharing dialog box. You can generate multiple shareable links with different levels of access for the same map.

If someone uses the shareable link to access the map, they will be given the specified level of access to the map and the map will be bookmarked in their account. If they close the map, they will be able to access it again with the same level of access by going to Your Bookmarks.

QR Codes

When you generate a shareable link, CalTopo also creates a QR code to represent that link, which appears to the right of the sharable link. To view the QR code, click on the QR icon at the end of the shareable link. A separate tab displaying the QR code will open.

Each QR code displays the map ID and the type of access below the QR code itself. In the example above, the map ID is 11FC and the type of access is Read. Users can scan the code displayed on the screen or the image can be printed for users to scan.

QR codes can also be shared through text or email. If you choose to email the QR code, it's a good idea to send both the shareable link and QR code so that users can open the link either on their computer or mobile device.

The best way to scan QR codes is by using the CalTopo mobile app. From the three-bar menu in the upper lefthand corner, select Scan QR Code. The screenshot below is from the iOS mobile app but it is the same in the Android mobile app.

Enable your phone to allow CalTopo access to the camera. The camera will then open with an orange scanning box displayed on the screen. Align the box with the QR code; it will read automatically and then turn teal once it has successfully recognized the code.

Upon recognizing the code, the mobile app will open that map with the specified level of access and add it to your bookmarks. You must have a network signal to be able to open the map for the first time.

If you are the owner of the map, you can generate shareable links and QR codes in the mobile app as well. With the map open, click Show Details in the 3 bar menu, which will open the Map Details screen.

The icons for creating shareable links look a little different on the Map Details screen in the iOS and Android mobile apps:

In the iOS mobile app, click the export icon to create a shareable link and then select the correct access level.

In the Android mobile app, click the share icon to create a shareable link and then select the correct access level.

To create QR codes on either the iOS or Android mobile app, click Generate QR Code at the bottom of the Map Details screen and select the correct access level.

QR codes will be especially useful for the first responder community where mutual aid and large incidents require sharing maps with a lot of people. We can also see this being useful for guides to share maps with clients or if you make a map at the trailhead and need to share it with your buddy before beginning your hike.