[OSM-dev] A PostgreSQL extension for real-time simplification of objects in OSM API database

[RTOSM DOOPAS]

Yes, osm2pgsql/imposm are very useful tool.

While the osm2pgsql and imposm are used to import data from API
Database to a PostGIS instance. With the PostGIS, user can perform
tile rendering or geospatial computing.

The purpose of the osm2pgsql/imposm is different. rtosm aims to make
the API database more flexible and versatile to have the ability to
answer following queries :

"select the national boundary of U.S. in 1000 (or any other number,
you name it) nodes and tell the simplification error of it"

So user can draw any huge features in real-time in browser or JOSM
with its simplified version. the online data editing and online data
viewing can be more efficient.

let's take an example, The relation with ID 6038068 (islands of
Britain)  is comprised by 4596 ways and 634414 nodes. without
simplification, even with a naive simplification which only preserve
the start and end point of of each way will result in 4596 nodes to
represent the feature, it is hard to visualized and manipulated with
so many nodes retrieved from database. The rtosm can simplify the
relation with any number of nodes.

In short, rtosm is about to extend the OSM API to make it support
viewing and editing data at any scale directly from database.

On Wed, Nov 16, 2016 at 6:36 AM, Darafei "Komяpa" Praliaskouski
<me at komzpa.net> wrote:
> Hi!
>
> Have you tried osm2pgsql and/or imposm? What is the reason to do it over API
> db schema?
>
> вт, 15 нояб. 2016 г. в 19:27, RTOSM DOOPAS <rtosmdb at gmail.com>:
>>
>> Hi,
>>
>>
>>
>> I have written a small extension for OSM API database to offer the
>> functionality of real-time simplification of objects (ways, relations) by
>> node filtering during the query processing. The idea behind it is as
>> followings:
>>
>>
>> 1. For each spatial object such as way or relation, attach weight value to
>> each component node by geometric computation.
>>
>>
>> 2. In processing query, only retrieve nodes with the top k weight.
>>
>>
>> 3. Assembly the simplified objects with filtered nodes.
>>
>>
>>
>> In fact, there are some really complex concepts, algorithms and data
>> structures in the extension, but the essential idea is that simple.
>>
>>
>> With this extension, The OSM API database will have the ability to answer
>> windowing query with arbitrary size by a “top k” operator to limit the
>> output volume of the results.
>>
>>
>> The purpose of the extension is to make the OSM API database can serve
>> data in any scale like the tile server can do.
>>
>>
>>  The codes in the extension is a bit of preliminary. However, to make the
>> idea work, Not only the code need to be examined and tested, but also the
>> database must be “normalized” to take the advantages of this extension.
>>
>>
>> The code is hosted in github, https://github.com/rtosm/rtosm
>>
>>
>> The "rtosm" means a database for real-time openstreetmap. Welcome to
>> comment.
>>
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