map180 is a Go (golang) library for drawing SVG maps with markers on EPSG:3857.

• It handles maps that cross the 180 meridian
• Allows high zoom level data in a specified region.
• Land and lake layer queries are cached for speed.

Once you have a database with the map data loaded (see below) drawing a map is as simple as:

wm, err = map180.Init(db, `public.map180_layers`, map180.Region(`newzealand`), 256000000)
b, err := wm.SVG(...)

See the Go docs for further details.

Postgres 9.* with Postgis 2.*

• Create the tables (and associated indexed) public.map180_layers and public.map180_labels. See etc/nz_map180_layer.ddl
• Load the data e.g., for the fits db: psql -h 127.0.0.1 fits postgres -f data/new_zealand_map_layers.ddl

If necessary change the schema, table, and user access as required. They can be specificed in map180.Init()

The goal is to end up with land and lakes multi polygon on EPSG:3857 entered into public.map180_layers and labels in public.map180_labels. The zoom region should include data for your region of interest at higher zoom levels.

The assembled New Zealand data set (data/new_zealand_map_layers.ddl) was made from shape files that where loaded into the DB and then cut and transformed into public.map180_layers and public.map180_layers.

The files etc/load-nz-shp.sh and etc/nz_map180_layer.ddl document the process of creating public.map180_layers. This was then dumped using:

pg_dump -h 127.0.0.1 --table=public.map180_layers --table=public.map180_labels --data-only -U postgres  fits -f data/new_zealand_map_layers.ddl

The assembled New Zealand data set uses data sourced from:

• Natural Earth - http://www.naturalearthdata.com/
• the LINZ Data Service http://data.linz.govt.nz which is licensed by LINZ for re-use under the Creative Commons Attribution 3.0 New Zealand licence.