It may be worth looking at SomeoneElse’s LUA script for inspiration: it’s a very rich source for ways to process a wide range of things using LUA & osm2pgsql. I suspect that pre-processing names in LUA might be easier than writing stored procedures. There is also the use of a relatively simple polygon to process specific name rules (in this case preferring name:cy in areas with >40% Welsh speakers), which may be relevant to Nepal.
I guess the trade off is time spent loading the database if you decide to change the LUA script versus time rendering a map if you do the logic in a Postgresql stored function.
I used to have a pretty custom osm2pgsql.style and found it a pain if I wanted to use a “new to me” tag. So I have recently gone to using the tags hstore for accessing things not in the default osm2pgsql.style. That allows a bit faster turn around time if I want to test some new rendering.
But maybe once I’ve settled in on a way to handle tags it might be worth moving the logic from the mapnik XML style and/or Postgresql stored function to a LUA script to speed up production of final PDF print maps.
I think you can still use hstore & have the best of both worlds. Another trick I use is to load into tables not using planet_osm_ and create views with the default names which allows a fair amount of additional jiggery-pokery (but I more of less learnt SQL by writing huge views because the software I worked with could only cope with 1 SQL statement at a time & DBAs were OK with views but more or less nothing else).
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تعليق من SK53 في 28 ديسمبر 2019 في 10:25
It may be worth looking at SomeoneElse’s LUA script for inspiration: it’s a very rich source for ways to process a wide range of things using LUA & osm2pgsql. I suspect that pre-processing names in LUA might be easier than writing stored procedures. There is also the use of a relatively simple polygon to process specific name rules (in this case preferring name:cy in areas with >40% Welsh speakers), which may be relevant to Nepal.
تعليق من n76 في 28 ديسمبر 2019 في 13:38
I guess the trade off is time spent loading the database if you decide to change the LUA script versus time rendering a map if you do the logic in a Postgresql stored function.
I used to have a pretty custom osm2pgsql.style and found it a pain if I wanted to use a “new to me” tag. So I have recently gone to using the tags hstore for accessing things not in the default osm2pgsql.style. That allows a bit faster turn around time if I want to test some new rendering.
But maybe once I’ve settled in on a way to handle tags it might be worth moving the logic from the mapnik XML style and/or Postgresql stored function to a LUA script to speed up production of final PDF print maps.
تعليق من SK53 في 28 ديسمبر 2019 في 15:29
I think you can still use hstore & have the best of both worlds. Another trick I use is to load into tables not using planet_osm_ and create views with the default names which allows a fair amount of additional jiggery-pokery (but I more of less learnt SQL by writing huge views because the software I worked with could only cope with 1 SQL statement at a time & DBAs were OK with views but more or less nothing else).
تعليق من Harry Wood في 30 ديسمبر 2019 في 22:35
I see you’ve blogged a fair bit about OpenStreetMap. We could add your blog, or just the OpenStreetMap category: https://retiredtechie.fitchfamily.org/category/openstreetmap/ to http://blogs.openstreetmap.org if you fancy it!
تعليق من n76 في 30 ديسمبر 2019 في 22:42
Sure. I am unaware of the mechanism for adding https://retiredtechie.fitchfamily.org/category/openstreetmap/ to http://blogs.openstreetmap.org so someone else would have to do it.
But I have no objections. I’ll just have to remember that if I categorize something as OpenStreetMap it will automatically show up elsewhere.