Extension:Kartographer

Kartographer is an experimental extension to add Maps to Wikis. It is very similar to Maps extension, but its functionality will be specifically targetting Wikimedia communities such as Wikivoyage and Wikipedia.

Goals

 * A simple method to insert a map into an article without requiring common.js code changes
 * Ability to add extra information (marks, area, popups, text, links) to the map
 * Ability to generate static images on the server with all the extra layers (faster loading, allows to print)
 * Ability to incrementally add features to the map. For example, each usage of the restaurant template in WikiVoyage adds a single point of interest (POI), and the map shows all of them.
 * Multiple items added` independently need to be indexable. E.g. the first restaurant template would show [1] on the page, and map would show POI as a clickable [1] element. There could be multiple index counters at the same time, each for its own type of POIs.
 * Ability to gather map usage statistics (KPI) to better gauge how and what should be improved.
 * Path for experimentation - if the user is aware of the privacy implications, the map should be able to show external data from non-production source, e.g. wmflabs. TBD: Static, server-side rendered images will not include the extra data added via this method until the extra data source is hosted in the secure production environment and can be shown without the user action.

Usage Ideas
This sample inserts a map of a given zoom and location (center) as a static image, and shows a museum icon. Once clicked, it will expand full screen and become interactive - users will be able to drag, zoom and interact with the icon.

Data Layers
The content of the tag has to be either empty or a valid GeoJSON with styling. The tag's content may also contain any template expansions, such as Template:TemplateName or default value. This should not cause any problems because the "{{ " is an impossible construct in JSON. The styling will probably be done using the simplestyle 1.1 specification with Maki icons (CC0).

Map Modes

 * Show the map as a static image, but when clicked, it will become interactive. This allows much faster initial map loading, and saves on bandwidth and device power until user actually wants to browse the map.
 * Same as, but instead of expanding on click to full screen, the existing static map will become interactive without changing its size.
 * Show provided wiki markup as a link. Clicking the link shows a map as a popup window of a width x height size or as full screen if width/height are not given.
 * Do not output any wiki markup, but store the data to be used by another map tag.

Combining Data (for Wikivoyage & Lists)
Wikivoyage tends to have a large number of POIs, such as museums and restaurants, listed on a page. Each POI is usually added with a template, but all of them should appear on the same map. Also, each POI should be referable by showing an icon with a number, both in the text of the article, and on the map.

To help with that,   has a data mode. All features of all  tags in data mode will be combined together, in the order appearing on the page, and can be shown together by using   attribute.

Could expand to this - a clickable link with an icon that brings up a map, followed by POI description:

In the above, "NumberedDivIcon" is a plugin that adds JS icon code for leaflet and gets replaced with this HTML:

Somewhere else on the page, all data can also be shown at once:. Data attribute could also use a specific group name, or a comma separated list of groups:. The grouping concept allows us to have more than one list on the same page and not show them in the same map. We could even introduce cross-page by specifying  value to point to the data on another page.

If the same icon needs to be shown on the page again:

Why Is This So Complicated?

 * A popup link, like the green square here, needs to be a tag with JavaScript, so it has to be generated by MediaWiki
 * The popup's appearance must be customizable by the community
 * Part of the link's appearance must be the sequential index, in the order of appearance on the page. We do not support any parser functions with a state, such as counters, for performance reasons (parallelism). Cite extension has an elaborate way of working around this problem, and we would have to implement something similar, including Parsoid support.
 * The appearance of the link, such as the green square, needs to be the same in three places: on wiki page, on the map rendered client-side with Leaflet, and on the map when rendered in the Kartotherian's static service. So even though it will be rendered by different systems (i.e. HTML, Canvas, SVG, WebGL), the code that generates should hopefully stay in one place.