We need to pick a source for icons for brighmed. We can design our own icons, but I want to leverage others work for most of the icons.

The current OSM Bright fork relies on Maki1 icons, which are no longer being maintained or added to, so there are good reasons to switch. The technical requirements of the icons are

• Available in SVG
• Only use SVG features that Mapnik supports
• Pixel-aligned
• Simplified for the small scale

A point that may not be obvious is that icons can't simply be re-scaled because they need to be pixel aligned for clarity.

This is on a 15x15px grid, and if you scaled the icon to a 16x16 grid the edges wouldn't line up with pixel edges and it would become blurry. https://github.com/gravitystorm/openstreetmap-carto/issues/632 contains more details, including more advanced techniques which I don't suggest (custom fonts, externally doing the svg->png conversion at higher quality).

Maki handles this well, with different versions of each icon at 11px and 15px sizes.

In addition to the technical requirements, the cartographic requirements are

• Avoid excessive detail
• Avoid perspective
• No halos
• Different versions whenever icons of multiple sizes are needed

Some guidelines which have similar requirements:

• https://github.com/gravitystorm/openstreetmap-carto/blob/master/CONTRIBUTING.md#map-icon-guidelines
• https://www.mapbox.com/maki-icons/guidelines/

The major icon collections are

• Maki1 (no website, https://github.com/mapbox/maki/blob/mb-pages/www/images/maki-sprite%402x.png for icons). This is what OSM Bright uses, but is unmaintained. It has 12px, 18px, and 24px versions of icons
• Maki2 (https://github.com/mapbox/maki). This is not a drop-in replacement for Maki1. It has different icon coverage, but after the coverage improvements for iD should have most of what we need. Icons are 11px and 15px. About 150 icons of each size.
• Osmic (https://github.com/gmgeo/osmic): About 150 icons, mainly single-size.
• OpenStreetMap Carto (https://github.com/gravitystorm/openstreetmap-carto/tree/master/symbols). OSM-carto isn't an icon collection, but has one for everything it renders, and because it renders so many things, it is quite extensive.
• Fontawesome (http://fontawesome.io/icons/ + https://github.com/encharm/Font-Awesome-SVG-PNG) Limited map-related icon coverage, but it has some, and lots of general purpose icons.

If we were to use Maki1 we should take of maintenance of it and backport the technical and script improvements from Maki2. Maki2 suffers the disadvantage of a risk of making the map look like a Mapbox clone.

I'm not sure what I'm going to use in the short-term since I've started needing icons already.