Emergency communications map browser application
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Live multi-user annotatble map for emergency communications

Home page



Demo server


  • Interactive map with symbols for operators, locations, and incidents
  • Incidents defined by geographic region and time
  • Text-based message traffic with associated precedence (e.g. priority, emergency)
  • Attach files to messages
  • Operator status reports
  • Location status reports
  • Tactical call signs
  • Upload locations by latitude/longitude
  • Download message logs
  • Message sorting and location filtering
  • Persistent storage on server database, with replication


  • Can be encrypted (https) or unencrypted (http, suitable for Amateur Radio)
  • MESH networking
  • Internet / intranet
  • Relies on three server platforms, each of which can be deployed redundantly to avoid single points of failure:
    1. CouchDB
    2. Map tile server
    3. Web server (e.g. Apache2)

User manual

Installation (Ubuntu Linux)

This installation method has been tested on Ubuntu 16.04.5 (xenial). The process is not particularly pleasant, and if others have suggestions on how to improve it, please contact me.

CouchDB database (http://couchdb.apache.org/)

Install CouchDB (v1.6.0 tested)

$ sudo apt install couchdb

Edit the file /etc/couchdb/local.ini, for example using
$ sudo vi /etc/couchdb/local.ini

  1. Insert the line: enable_cors = true beneath the line that reads [httpd]

  2. Add the following lines to the end of the file:

origins = *
credentials = true
headers = accept, authorization, content-type, origin, referer, x-csrf-token

Restart CouchDB:
$ sudo /etc/init.d/couchdb restart

Set up databases using web configuration tool. Direct your browser to http://<host>:5984/_utils/, where <host> is the hostname or IP address of the CouchDB server

  1. Set an admin password. A link in the lower right-hand corner of the web page should give you the option of setting an administrator password.

  2. Verify the installation. There is a link to do this on the right hand side of the page, below Diagnostics.

  3. Create databases for EmComMap.

    • Click Overview, which is below Tools on the right hand side
    • On the upper left, click Create Database
    • Create a database called emcommap
    • Using the same method, create a second database called emcommap_attachments

To create users:

  1. Click Overview, which is below Tools on the right hand side

  2. On the left, you will see a link to the database _users. Click on it.

  3. Click New Document on the upper left, which will bring up a document containing one line

  4. Click the Source tab on the upper right

  5. Double-click on the document to get into edit mode, and replace the document's text with the following:

    "_id": "org.couchdb.user:username",  
    "name": "name_of_user",  
    "type": "user",  
    "roles": [],  
    "password": "plaintext_password"  
  6. In the text, replace username with the desired user name, name_of_user with the user's name, and plaintext_password with the user's password (it will be stored as a hash, not in plain text).

  7. Click Save Document in the upper left corner

You must give each user that you create permission to access the EmComMap databases, as follows:

  1. Go to Overview (below the Tools menu on the right).
  2. Click on the database emcommap
  3. Click on Security at the top
  4. You will add to the Members area of the dialog which pops up. In the Names field you will fill in all user names using the following format: ["user1","user2","user3"]
  5. Click Update to complete.
  6. Repeat these same steps for the database emcommap_attachments

Apache2 web server (https://httpd.apache.org/)

Note that while Apache2 is used in this example, other web servers should perform just as well.

Install the apache2 web server:
$ sudo apt install apache2

Download EmComMap
$ cd /var/www/html
$ sudo git clone https://github.com/DanRuderman/EmComMap.git

Restart the apache2 web server
$ sudo apache2ctl restart

Map tile server (https://github.com/klokantech/tileserver-gl)

Create a directory for the tile server data:
$ sudo mkdir /usr/local/tileserver-gl
$ cd /usr/local/tileserver-gl

Download map tiles from OpenMapTiles. You can download the entire planet or just a region of interest by navigating to that location. For this exmple we will download the Los Angeles region. Whichever geographic area you choose, you will want to download the OpenSteetMap tiles. Note you will need to create an account to download tiles. OpenMapTiles will provide you a wget command to download. Download into the directory you created above (e.g. /usr/local/tileserver-gl).

$ sudo wget -c https://openmaptiles.com/download/<TOKEN>/osm-2017-07-03-v3.6.1-california_los-angeles.mbtiles?usage=personal

Unfortunately, the filename ends up with an odd suffix, which can be fixed using mv:
$ sudo mv osm-2017-07-03-v3.6.1-california_los-angeles.mbtiles\?usage\=personal osm-2017-07-03-v3.6.1-california_los-angeles.mbtiles

Install docker:
$ sudo apt install docker.io

Run the tile server (must be in the directory containing the tiles, e.g. /usr/local/tileserver-gl):
$ sudo docker run --rm -it -v $(pwd):/data -p 8080:80 klokantech/tileserver-gl

The first time this is run, the docker container for tileserver-gl will be downloaded and extracted. This will take significant time (perhaps 30 minutes). When initialization has complete and the tile server is active, it will print: Startup complete. At this point it will be serving tiles over port 8080 using the unencrypted http protocol.

To test that the tile server is functional, enter the following URL into your browser:
http://<host>:8080/styles/klokantech-basic/0/0/0.png(substituting your host name for <host>). It should bring up a single tile of the world.

It is useful to place the above docker command into a shell script, and possibly have it run automatically on reboot via the /etc/init.d mechanism. Documentation on tileserver-gl can be found here.


EmComMap configuration

To configure your installation, edit the file /var/www/html/EmComMap/html/config.js. Toward the top of the file you will see these lines:

const RUN_LOCATION = "local";

if(RUN_LOCATION == "my-install") {
    var TILE_SERVER = 'http://<host>:8080/styles/klokantech-basic/{z}/{x}/{y}.png';
    var TILE_SERVER_OPTS = {
	maxZoom: 18,
	attribution: 'Map data &copy; <a href="https://www.openstreetmap.org/">OpenStreetMap</a> contributors, ' +
	    '<a href="https://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, ' +
	    'Server courtesy of <a href="https://openmaptiles.com/">OpenMapTiles</a>'
    var DEFAULT_DB_HOST = '<host>';

Within them, change the following:

  1. Change the RUN_LOCATION string to my-install instead of local
  2. Change both instances of <host> to the name or IP address of your EmComMap server. Note that if you have the CouchDB server on a different computer, then use that computer's address for DEFAULT_DB_HOST.

Set the value of ADMIN_EMAIL to be the email address for credentials requests.

Additionally, if your deployment is for testing only set the value of TEST_MODE to true in config.js. This will put the text TESTING in bold red font at the top of the application and precede all messages with "TESTING:". The purpose is to ensure that test traffic is not mistaken for a real-world emergency.

Database replication

Although I have not attempted it, it should be straightforward to replicate the CouchDB databases across servers, thus providing a route to failover. Please consult the CouchDB documentation on how to achieve this.

Note on encryption and Amateur Radio use

Amateur radio based applications (e.g. supporting MESH networking) may not encrypt data transmissions.

  • CouchDB does not by default enable encryption, as it uses the http rather than the https protocol. The relevant lines in the configuration files (/etc/couchdb/default.ini and /etc/couchdb/local.ini) contain the text httpsd, and are by default commented out. The default port for CouchDB's https encrypted communications is 6984, so if you run the command $ netstat -plnt | grep 6984, you should see no output unless CouchDB is listening on an https socket. If you wish to enable SSL based encryption, see this article.

  • Apache2 does not by default enable encryption over SSL. To check that the SSL port (443) is not open, run the command $ netstat -plnt | grep apache2, which should only show a line for port 80 and not for port 443. If you wish to disable SSL, comment out any lines containing Listen 443 in the file /etc/apache2/ports.conf.

  • Tileserver-gl as installed above does not use encryption.

Thanks to those who kindly provided these software libraries leveraged by EmComMap:

Dan Ruderman (K6OAT) emcommap@gmail.com