Add Tax Map

[chriswhong]

http://gis.nyc.gov/taxmap/map.htm

Nice to have: snap-to-tax-lot (can be toggled on/off)

[chriswhong]

• [x] research feasibility of programmatically obtaining PDFs from the DoITT digital tax map AND overlaying user-drawn geometries (this may imply using the rasterized PDF as a map overlay)
• [ ] Implement!

[chriswhong]

After a lot of experimentation yesterday, I think getting a workable tax map into this app is going to be a heavy lift, and not feasible in our short window during this push. Some notes:

• There is value in using the pre-made block-level official Tax Maps that DoITT/Finance provide. These are what is required in the current standard, and much effort has gone into making them.

• A feasible approach may be to bring these PDFs into the app, saved with the project somehow, and allow the user to draw on top of them by creating SVG overlays.

• We attempted to re-create the Digital Tax Map as a standalone vector tile service. We had a prototype of this working, but hit some label collision issues and overall realized that reproducing the work of the DoITT maps is duplicative and really hard, and because these are legal documents, we should not take this undertaking lightly.