RIAL ESTATE — MILAN GEOGRAPHIC DATA

Map data © OpenStreetMap contributors.
Source and contributor information: https://www.openstreetmap.org/copyright

The adapted geographic database in this directory is made available under
the Open Data Commons Open Database License (ODbL) v1.0:
https://opendatacommons.org/licenses/odbl/1-0/

You may copy, use and adapt these data, including commercially, subject to
the attribution, share-alike and access requirements of that license.
The license applies to the identified geographic data, not to unrelated
website software, branding, property photographs or other site content.
The data are provided without warranties; consult the full license above.

DOWNLOADS (relative to this directory; no registration or payment)

manifest.json   Geographic bounds, centre, extent, classes and dataset date
buildings.bin  Building footprint rings and building heights
roads.bin      Road, rail and canal polylines and their classes
areas.bin      Water, park, woodland and cemetery rings and their classes

These are the complete adapted geographic files loaded by the map, not
preview samples. Each file is directly accessible over HTTP. The rendered
roofs, facades and vegetation are decorative interpretations, not surveyed
details of individual properties. Apartment listings are separate content.

The download page adds ?v=<URL-encoded manifest.generatedAt> to each binary
URL, matching the renderer's versioned requests. Unversioned URLs and this
documentation are revalidated; versioned geometry can be cached.

ADAPTATIONS

Rial Estate extracts a Milan bounding box from OpenStreetMap, filters small
or unsupported features, simplifies rings and lines, projects coordinates
to local metres and quantizes them to unsigned 16-bit coordinates. Heights
are taken from source height/level tags where available; missing heights
are estimated from building type with deterministic variation. The date
and geographic bounds of this extract are recorded in manifest.json.

MACHINE-READABLE BINARY FORMAT (RIA1)

All integers are little-endian. There is no compression or encryption.
Each file is a sequence of these arrays:

  byte 0:               uint32 magic = 0x52494131
  byte 4:               uint32 featureCount = N
  byte 8:               uint32 totalPointCount = P
  byte 12:              N uint16 point counts, one per feature
  byte 12 + 2*N:        N uint16 attributes, one per feature
  byte 12 + 4*N:        2*P uint16 coordinates, interleaved x,z

Read each feature's number of points from the counts array and consume that
many x,z pairs from the shared coordinates array. For buildings and areas,
connect the last point back to the first to close the ring; road features
are open polylines. Attributes are height in decimetres for buildings and
zero-based class indices for roads/areas (see manifest.json for classes).

Let E = manifest.extent. Decode each unsigned coordinate q as:

  metres = (q / 65535) * 2 * E - E

The local origin is manifest.center. X increases eastward and Z southward.
To recover longitude/latitude in degrees from the local metre coordinates:

  longitude = center.lng + x / (111320 * cos(center.lat * pi / 180))
  latitude  = center.lat - z / 111320

The licence notice and URL above must accompany redistributed copies of
these data, including when they are converted to another format.