The Pelias Interpolation engine currently uses two SQLite databases for storing street and address information. This document explains the most important tables in these databases and the meanings of the various fields.
The street database contains several tables with data regarding streets.
| field | type | description |
|---|---|---|
| id | INTEGER |
the primary key for a given street |
| line | TEXT |
polyline encoded linestring |
The polylines table contains a unique identifier for each street, as well as its geometry as a
polylines encoded string with precision 6.
Tools for working with polyline-encoded strings include:
- @mapbox/polyline Node.js package
- polyline Python package.
The names table contains information on names for a given street. Streets can have multiple names,
so there may be multiple rows in the names table for a given row in the polyline table.
| field | type | description |
|---|---|---|
| rowid | INTEGER |
the primary key column for this table, not generally referenced |
| id | INTEGER |
a foreign key to the corresponding row in the polyline table |
| name | TEXT |
the name of the street |
The address database contains a single table with information on notable points associated with streets. These points might represent an exact address, the start or end of an address range, or merely a point along a curved street.
| field | type | description |
|---|---|---|
| rowid | INTEGER |
the primary key column for this table, not generally referenced |
| id | INTEGER |
a foreign key to the corresponding row in the polyline table |
| source | TEXT |
the datasource for this point |
| source_id | TEXT |
a unique identifier for this point from the original datasource (if applicable) |
| housenumber | REAL |
an exact or interpolated housenumber for this point |
| lat | REAL |
the latitude of this address point |
| lon | REAL |
the longitude of this address point |
| parity | TEXT |
Either L or R if this is an exact address, denoting the side of the street the address is on |
| proj_lat | REAL |
The projected point along the related street corresponding to this address |
| proj_lon | REAL |
The projected point along the related street corresponding to this address |
The source field stores information on the origin of this particular address point. There are several options:
- OA: this point is an exact address from OpenAddresses
- OSM: this point is an exact address from OpenStreetMap
- TIGER: this point is derived from an address range from TIGER
- VERTEX: this point represents a vertex along a curved street
The housenumber field contains the housenumber associated with this point. It will be an exact housenumber for records from OSM or OA, or a decimal value for vertex points along the street.
These fields contain the coordinates of this point.
For exact addresses from OSM and OA, or address range points from tiger, the coordinates the exact location of an address. This point is likely some distance away from the corresponding street.
For vertices, this is the exact point along the street where this vertex lies.
These fields are only present for exact address or address range points. They represent the orthogonal projection of this address point along the corresponding street.
In the image from the interpolation demo interface below, the red pins represent the
address points, and the dashed red line connects the address points to their corresponding projected
point along the street. The orange pins represent VERTEX points.
This image shows a street with addresses on each side. The interpolation engine has detected which
addresses are on the left (red) and right (blue). In this case left and right describe the side of
the street when looking in the direction of increasing housenumbers.
