Redesign Sources field for more structured tagging

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OpenHistoricalMap/iD#78 OpenHistoricalMap/iD#145 added the Sources field to every preset for every feature, making it appear by default due to its importance. It also continues to appear on the changeset upload screen, as in OSM’s version of iD. However, we’ve eliminated the dropdown options for things like “Local Knowledge” and “Survey” because we expect mappers to normally set source to a citation of a published work.

This is the main tracking issue for an idea first described on this wiki page and later incorporated into an accepted Google Summer of Code proposal by @pedromml:

The OpenHistoricalMap project aims to give a temporal aspect to mapped information, adding the possibility to see maps during specific points in time. To do that, features can be provided a start date, an end date and the historical source where the data comes from. For the source, in ID, the javascript OpenStreetMap editor, there is a “Sources” field for every feature, but the field is simply a plain text field. To provide a more structured way of providing sources, that field should be updated or replaced in a way that helps users format their citations. The goal of this project is to implement a WYSIWYG interface for the sources field in the ID editor to provide a better way to register sources, alongside new validations to support the correct usage of this new interface.

[1ec5]

Some assorted notes:

The documentation about source=* covers many details, but almost nothing is set in stone yet. If there’s anything that doesn’t seem practical from your perspective, please note it so we can give it some more thought. Pay particular attention to the ideas about providing multiple sources on the same feature, either as an ordered list or attached to arbitrary keys like start_date. There’s no precedent for something like this in iD yet.

The existing Source field is being monkeypatched into iD’s internals, but eventually we’ll probably want to maintain these customizations as a real fork: #777. Don’t worry about it for now; having it all in the same repository will probably simplify your workflow as you iterate on the feature. At build time, schema-builder compiles the preset and field metadata in id-tagging-schema and name-suggestion-index metadata into some large JSON files that the browser loads over a CDN. The OHM customizations follow the same format in JavaScript. The schema-builder documentation will help you understand which options are already available that you don’t have to build from scratch.

OSM’s tagging system, and thus OHM’s, is very freeform; mappers can technically come up with any tag, not just the ones that are documented. We have an instance of taginfo that gets you an idea of which tags are popular among mappers. Since the project is still young, OSM’s taginfo is also useful for learning the general patterns for creating tags (though OSM has a lot of historical baggage from abandoned experiments and deprecated tagging schemes).

[1ec5]

@pedromml finished this project successfully with the following PRs:

• OpenHistoricalMap/iD#217
• OpenHistoricalMap/iD#222
• OpenHistoricalMap/iD#223

This forum thread has a summary of the changes.