{"action":"created","issue":{"url":"https://api.github.com/repos/CartoDB/mapnik/issues/15","repository_url":"https://api.github.com/repos/CartoDB/mapnik","labels_url":"https://api.github.com/repos/CartoDB/mapnik/issues/15/labels{/name}","comments_url":"https://api.github.com/repos/CartoDB/mapnik/issues/15/comments","events_url":"https://api.github.com/repos/CartoDB/mapnik/issues/15/events","html_url":"https://github.com/CartoDB/mapnik/pull/15","id":153484097,"number":15,"title":"If there're overviews, just use them for rendering","user":{"login":"rafatower","id":1914276,"avatar_url":"https://avatars.githubusercontent.com/u/1914276?v=3","gravatar_id":"","url":"https://api.github.com/users/rafatower","html_url":"https://github.com/rafatower","followers_url":"https://api.github.com/users/rafatower/followers","following_url":"https://api.github.com/users/rafatower/following{/other_user}","gists_url":"https://api.github.com/users/rafatower/gists{/gist_id}","starred_url":"https://api.github.com/users/rafatower/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/rafatower/subscriptions","organizations_url":"https://api.github.com/users/rafatower/orgs","repos_url":"https://api.github.com/users/rafatower/repos","events_url":"https://api.github.com/users/rafatower/events{/privacy}","received_events_url":"https://api.github.com/users/rafatower/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2016-05-06T16:03:03Z","updated_at":"2016-05-19T11:14:38Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/CartoDB/mapnik/pulls/15","html_url":"https://github.com/CartoDB/mapnik/pull/15","diff_url":"https://github.com/CartoDB/mapnik/pull/15.diff","patch_url":"https://github.com/CartoDB/mapnik/pull/15.patch"},"body":"The current code falls back to the base table for small scales.\r\n\r\nThat approach has some drawbacks cause it forces the original table to\r\nshare some conditions with its overviews (same SRID, alginment, scale\r\nconstraints) for the rendering to work properly.\r\n\r\nWhat we propose is to always fall back to the highest resolution\r\noverview (lowest scale), rather than the original table, in order to\r\navoid coupling the original table with the constraints imposed by\r\nrendering and still have them linked (in postgis raster metadata).\r\n\r\nPlease note this approach is not 100% compatible as the base table\r\nwon't be used. This should be no big deal because overviews can have\r\nan arbitrary resolution/scale.\r\n\r\n---\r\n\r\nThis is a cherry-pick from the change I proposed for master here: https://github.com/mapnik/mapnik/pull/3424\r\n\r\nfor the record, all the existing tests pass locally with a clang 3.5 build:\r\n```\r\n(test) ubuntu@cdb:~/src/misc/mapnik$ make test                                                                                                                                                                                                 \r\n./run_tests\r\n*** Running C++ tests...\r\n............\r\n\r\n*** Running visual tests...\r\n...............................................................................................................................................................................................................................................\r\n...............................................................................................................................................................................................................................................\r\n...............................................................................................................................................................................................................................................\r\n.........................................................................................................................................................................................................................................\r\nAll 950 visual tests passed: ✓ \r\n*** Running python tests...\r\n..........................................................ERROR 4: `/home/ubuntu/src/misc/mapnik/tests/python_tests/../data/raster/this_file_should_not_exist.tif' does not exist in the file system,\r\nand is not recognised as a supported dataset name.\r\n\r\n...............................................................................................................................................................................................................................................\r\n..............................................................................................................................................................................................................................\r\n----------------------------------------------------------------------\r\nRan 519 tests in 30.632s\r\n\r\nOK\r\n```\r\n\r\nNote the pgraster tests, which were based on the python bindings, were moved out of the main project to the https://github.com/mapnik/python-mapnik project in the master branch."},"comment":{"url":"https://api.github.com/repos/CartoDB/mapnik/issues/comments/220295298","html_url":"https://github.com/CartoDB/mapnik/pull/15#issuecomment-220295298","issue_url":"https://api.github.com/repos/CartoDB/mapnik/issues/15","id":220295298,"user":{"login":"rochoa","id":45346,"avatar_url":"https://avatars.githubusercontent.com/u/45346?v=3","gravatar_id":"","url":"https://api.github.com/users/rochoa","html_url":"https://github.com/rochoa","followers_url":"https://api.github.com/users/rochoa/followers","following_url":"https://api.github.com/users/rochoa/following{/other_user}","gists_url":"https://api.github.com/users/rochoa/gists{/gist_id}","starred_url":"https://api.github.com/users/rochoa/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/rochoa/subscriptions","organizations_url":"https://api.github.com/users/rochoa/orgs","repos_url":"https://api.github.com/users/rochoa/repos","events_url":"https://api.github.com/users/rochoa/events{/privacy}","received_events_url":"https://api.github.com/users/rochoa/received_events","type":"User","site_admin":false},"created_at":"2016-05-19T11:14:38Z","updated_at":"2016-05-19T11:14:38Z","body":":shipit: "}}