migurski/TileStache — pull request #77 by thegreat (2012-07-18 01:07:52+00:00)
Title: merge_grids() still needed

This reverts commit 57b0ee08ce4c48e38c91175bfd4b21a4314afb66.

Mapnik.py merge_grids is used when the layer_id_key argument is provided. It was removed with ffa3c0621b645e706a1e586bb4f4ee224c0817e0 and 57b0ee08ce4c48e38c91175bfd4b21a4314afb66 which were merged around the same time as layer_id_key was added.

It would be nice to get the layer key identifier functionality into mapnik's renderer, but currently mapnik.render_layer() doesn't even support multiple layers with different datasources (see https://github.com/mapnik/mapnik/issues/1325).