Installing and Running the CalTopo Desktop App - macOS

NOTE: These instructions do not apply to mobile devices and is desktop software is not required for use on a mobile device. See mobile download instructions at:

To install the CalTopo Offline App you will need:

  • CalTopo App
  • CalTopo map data for your desired area
  • Java Standard Edition JDK

** Catalina OS users, please scroll down to the bottom for specific instructions. **

Installation Instructions

  1. Download and install the CalTopo app

    Decide whether you want to install CalTopo Offline on your computer's hard drive, a thumb drive or an external hard drive. Depending on how much map data you plan to download, it may not fit on your computer's hard drive. If you're not sure, start by installing it to your computer's hard drive now, it can be copied to another drive later if needed.

    Sign-in to your offline account on

    Click on your account name at the top of the left bar, then the "Offline Access" tab, or go directly to

    Click on "fresh install" and download the file to your computer.


    In Finder, go to the folder that contains the file (probably Downloads) on your computer. Double click "" to open it. The file is unzipped to a "caltopo" folder.


    For security reasons, MacOS requires you to move downloaded applications to a new location before running them. In Finder, open the "mac - read instructions" folder and drag the "CalTopo Offline" app into the "caltopo" folder above it.


    Now delete the "mac - read instructions" folder.


  2. Install Java Standard Edition JDK with the most up to date version, image shows Java 13, but newer versions may be available.

Go to, click on "Download JDK" under "Oracle JDK".


To download the installation file, click the link for "Mac OS".


Once the installation file is downloaded, open it to run it. Accept all of the default installation options.
  1. Download the map data.

    CalTopo Offline is installed without any map tiles, but includes a map downloader. To download map tiles for your desired area, follow the"Running CalTopo Offline" instructions below and then see the downloader documentation.

Running CalTopo Offline

CalTopo Offline is essentially the same program as Whereas is hosted by a web server in the Internet cloud, CalTopo Offline is hosted by a local web server on your computer. In both cases you use a web browser to interact with the server.

Therefore it takes two steps to run CalTopo Offline:

  1. Start the CalTopo Offline server (on Mac OS 10.14.X and older):

    In Finder, open the "caltopo" folder and right-click on the "CalTopo-Offline" file and select "Open".


    Your computer will ask if you are sure you want to run an app from an "unidentified developer". Click "Open".


    After the first time, you can run the app by just clicking on it.

    A CalTopo Offline console window will open. You can minimize this window, but don't close it.


    The server is now started and you can go to a browser to access the functionality.

  2. To Start the CalTopo Offline server (on Mac OS Catalina 10.15.X and newer)

Contact support

  1. Open a web browser (Chrome is recommended). On a new tab, go to http://localhost:8080.


    The server may take some time to get up and running. If initially you get a web page error (e.g. a “This webpage is not available” or "This site can’t be reached" message), then the local web server may need more time to get fully started. Wait for a few seconds and refresh the page.

Stopping the CalTopo Offline server

When you are finished using CalTopo Offline:

  1. Close the CalTopo Offline tab in your browser
  2. Click "Cancel" and then "Quit" in the CalTopo Offline Console


Accessing the CalTopo Offline server from another computer

If multiple computers are on the same Local Area Network (e.g. connected to the same router), each of the computers can connect to the CalTopo Offline server running on one of the computers. To do so, each computer opens an web browser and enters the Server Address displayed in the CalTopo Offline console (eg. http://My.Mac.local:8080).

Updating CalTopo Offline to a New Version

To update your version of CalTopo Offline, download a new version of the cal.jar file to your caltopo folder.

to your offline account on

Click on your account name at the top of the left bar, then the "Offline Access" tab, or go directly to


Click on "JAR only" and move the cal.jar file from your Downloads folder to your caltopo folder.

Mac OS Catalina Instructions

Follow the same installation instructions as above.

To run the program you will have to use the built-in Terminal.

  • To access the Terminal, in Finder, go to your CalTopo folder. Right click on the folder. At the bottom of the menu, hover over "Services" and click "New Terminal At Folder".
  • Enter the following command and press enter: chmod 755 cal.jar
  • From Finder, open the file CalTopo-Offline.bat with a text editor. Copy the text and paste it into your terminal window and hit enter.
    or copy the text here: java -Dsarsoft.version="CalTopo Offline" -Xmx1024m -jar cal.jar --debug=1

  • You should get something like: Welcome to CalTopo Offline version 4160, 04/28/20 02:33:06
    License Key 18813-A0E5V6 expires on 07/04/2021
    Temp data unpacked to /var/folders/ys/gpby69zd6jv224znlhzq5v2m0000gn/T/winstoneEmbeddedWAR
    Server Addresses: http://localhost:8080/

  • Open your browswer and navigate to localhost:8080

  • SARTopo should be running in your browser now.

To close the program, close the browser tab. Go to the Terminal window and type control-c to close the process.