I2D

Setting up an OHDM database with intermediate database

A fresh OHDM instance is usually set up by a OSM file which was parsed into the intermediate database.

In this second step, geo objects, geometries and their relations are extracted from those original osm data. This process has three steps: processing nodes, ways and relations.

The general idea is to split object descriptions and geometries to explicitly express the n-m-relationsship between object and geometries in each GIS

A geo object is considered to be an entity with some attributes which describes somewhat on earth. An object must have at least one attribute. Attributes are tags in OSM.

A geometry is the pure vector geometry describing the shape of an object. There is no geometry without an object.

In OSM, both concepts are combined.

Is just a geometry. There are no object information. This entry is required to be part of a way or relation.

1. Nodes are