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Markers4Map is an OpenSource tool developed for creating markers/icons with a info popup for the tagged geolocation on a map. The map is generated with OpenLayers and the mapping source OpenStreetMap.

The data for the markers, popups for the geolocation are stored in a JSON file and shared with others. Stored JSON data can be loaded from the WebApp Markers4Map.

The information about the markers/icons/popups is stored in link/url that can be used e.g. Wikiversity for a specific learning resource.

The documentation for Markers4Map is available in Wikiversity-Markers4Map.

The WebApp Markers4Map is a AppLSAC with privacy friendly data management in the browser in mind.

Display of the markers is performend with the following package:

Online Demo


The JSON data has the following structure.

vDataJSON["initdata"] = [
        "id": "2821",
        "lat": "51.493889053694915",
        "lng": "-0.14467470703124907",
        "title": "London",
        "summary": "London created a Open Innovation Ecosystem for SDG Clean Water and Sanitation",
        "has_detail_page": "1",
        "webpage": "",
        "id": "1508460902844",
        "lat": "51.243141",
        "lng": "-1.81185",
        "title": "Brimingham",
        "summary": "Birmingham created SDG-activities about SDG7 Clean and affordable Energy and SDG3 Health",
        "has_detail_page": "1",
        "webpage": "",

The init data is defined in docs/db/data.js in a Javascript file, so that the data can be loaded with a default script-tag.

Load and Save data

You can load and save data in the WebApp with the Load and Save. Saving the current work on the local harddrive as JSON file is always recommended because the processing of data is not stored on a server. Data is kept in the browser and is saved in the LocalStorage of the browser (see

Create your own JSON Editor with JSON2Schema

For JSON2Schema you can create a complete WebApp (AppLSAC) in 5 minutes from the given JSON to a full functional WebApp that performs the task in a browser as runtime environment without any need for setting up a server backend to be able to perform tasks with the WebApp. AppLSACs can run offline in browsers.

Browserify and Watchify

Browserify and Watchify are used in this repository to control the WebApp-javascript development with the required Javascript libraries installed with NPM Node.js and similar framework world that greatly improve your javascript workflow: Using them, you no longer need to micro-manage your script tags but instead you just declare the libraries each of your client-side modules is using - or you can even create your own reusable modules! Also, installing (or updating) javascript libraries is as easy as running a single command!

Global Installation of Browserify, Watchify, UglifyJS and DocToc

Requirement: NPM is intalled. Now call for global installation of Browserfy, Watchify, UglifyJS and DocToc by:

npm install -g browserify watchify uglify-js doctoc

This is recommended because your will not install Browserfy, Watchify and UglifyJS for all your repositories separately.

  • Browserfy converts node_modules in a single library, that can be imported in WebApp. Browserify resolves dependencies and included the required libraries into the bundled javascript code.
  • Watchify watches changes in the source code and runs the build process whenever it detects changes in the your source code.
  • UglifyJS compresses the source code of class_editor_uml.js into class_editor_uml.min.js to reduce download time and WebApp performance during load.
  • DocToc is used to create a helpful table of contents in the README (see DocToc-Installation for further details on NPM DocToc ). Run doctoc for updating the table of contents.
  • jsLint is used to check the Javascript code, quality of code can be improved by application of jsLint

Package Installation of Browserify and Watchify - Alternative

If your prefer that browserify and watchify is installed with your npm install command, save these to modules to your dev-dependecies in your package.json by calling

  • (Install Browsersify) npm install browserify --save-dev
  • (Install Watchify) npm install watchify --save-dev
  • (Install UglifyJS) npm install uglify-js --save-dev
  • (Install DocToc) npm install doctoc --save-dev
  • (Install jslint) npm install node-lint --save-dev

The difference between --save and --save-dev is, that development dependencies are installed with npm install because they are required for the development process of the code but they are not added to the generated Javascript-bundle that are used in the WebApp ClassEditorUML. The --save-dev commands for browserify and watchify will install the two modules with all the the dependencies in node_modules and add the dev-dependencies to your package.json.

"devDependencies": {
  "browserify": "^14.5.0",
  "watchify": "^3.9.0",
  "uglify-js": "^2.6.2",
  "lint": "^1.1.2"  

In the current repository Browserfy and Watchify are expected to be installed globally, because the package.json does not contain the dev-dependencies mentioned above.

Start Watching the Files with Watchify

Watchify will trigger the npm run build process if files were change due to alteration of code. To start watching the files, run the npm-watch script by npm run watch, which is defined in package.json

Source JS file and development bundle output

The main JS source file for the build process is src/main.js. The ouput library (resp. output file of build process) is stored in distrubtion library for browser based web-development in dist/bundle.js. Compressed code is generated with UglifyJS. It takes the dist/bundle.js as input file and creates the compressed file dist/bundle.min.js.

In this case the file bundle.js is markers4map.js and bundle.min.js is markers4map.min.js.

Main Library for Handling the JSON Database

Main library to handle large arrays is docs/js/editor4json.js

UML Diagram of Editor4JSON Class

UML Diagram of JS Class Editor4JSON

JSON Data and Schema

Default JSON Data

Default JSON data is defined in docs/db/data.json. If data is changes the alterations are stored in the LocalStorage locally in the browser.


The structure of the collected JSON data is defined by the JSON schema. The schema is defined in docs/schema/mapobject.schema. The schema for data collection can be defined by a JSON2Schema. Defined an example of a JSON record for a single collected item and create and use that as input for JSON2Schema. JSON2Schema takes the JSON as input and creates an appropriate JSON schema for the JSON. Additionally JSON shows with 5min how the final JSON editor will look like auf you can download the complete WebApp with the JSON2Schema as compressed ZIP file. Compression of the whole app is performed with JSZip. Furthermore JSON2Schema creates a Handlebars4Code Tempate template, which is in fact an extended HandlebarsJS Template Engine with additional helpers for code generation. The extended template engine is used to create output from a given JSON in a specific syntax (e.g. HTML for Map with markers). Try the generator for your JSON Editor.

Relevant Repository and Libraries

The following repositories are used for data collection.

Geolocation Selector

The repository openlayer_selectlocation are used to select a geolocation from an OpenLayers map.

Display Markers on the Map

The repository openlayer_display_markers to display all collected JSON records as markers with OpenLayers map.

JSON to Schema Generator

Used the following tool that creates a JSON schema for a provided JSON file. Used the given JSON file to create the JSON Schema with JSON2schema.html.


Special thanks to the following individual developers and teams of OpenSource JavaScript projects:

  • JSON-Editor by Jeremy Dorn. The JSON Editor takes a JSON Schema and uses it to generate an HTML form. The JSON-Editor is partially used to edit JSON file of the Javascript Project in JSCC . The schemes of the JSON subtree are stored in the folder /tpl of the JavascriptClassCreator. The full potential of the JSON-Editor was not used in JSCC . This can be approved in the future. The JSON-Editor of Jeremy Dorn has full support for JSON Schema version 3 and 4 and can integrate with several popular CSS frameworks (bootstrap, foundation, and jQueryUI). This would lead to major code reduction of JSCC . Refactoring of JSCC would make more use of the JSON-Editor features. Check out an interactive demo (demo.html):

  • Font Awesome Icons - 4.7.0 thanks to for providing the free 4.7.0 version for local application for this WebApp. The fonts in version 4.7.0 are created by Font Awesome and licensed under SIL OFL 1.1. The javascript-code for injecting the icon into the DOM licensed under MIT License. The Documentation for Font Awesome - 4.7.0 licensed under CC BY 3.0.

  • Developer Mihai Bazon create UglifyJS, a great tool to handle and parse Javascript Code and minify the Javascript code (see Source Code of UglifyJS).

  • The wrapper for UglifyJS is written Dan Wolff. His UglifyJS-Online example is used to minify/compress the exported Javascript code of generated JS Classes (For Online Example of the UglifyJS-Wrapper see source code on for the Online-Version of the Wrapper.

  • Developers of ACE Code Editor (Javascript Editing uses the Editor in iFrames)

  • FileSaver.js Developer Eli Grey provided the FileSaver.js that is used to store created JSCC files to the local filesystem. JSCC uses the same mechanism of browsers, that allows a Save as... in the context menu of a web pages or image. So not uncontrolled write access to your file system is implemented, because users have to select the locations in which the user whats to store the file (e.g. JSON, Javascript or HTML).

  • JointJS JointJS is a JavaScript diagramming library. It can be used to create either static diagrams. JointJS is used in this project to create UML-diagrams, that are interactive diagramming in conjunction and application builder in Javascript.

  • Inheritage for JavaScript with protoypes by Gavin Kistner

  • 3 ways to define a JavaScript class by Stoyan Stefanov

  • JQuery is used for the theme and standard operations in the Document Object Model (DOM) of HTML-pages. The JQuery-Themeroller was used to create a JQuery theme for JSCC.

  • FontAwesome by Dave Gandy used for the icons in HTML buttons


OpenLayers create a JSON Database of Markers for the Map




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