Sabbioneta

About and Goals

Mantua and Sabbioneta are an UNESCO site since 2008. This import procedure was proposed during the implementation of two cultural heritage projects focusing on Sabbioneta financed by Regione Lombardia and Fondazione Cariplo. These projects are described in details in this wiki page but one of the main objectives of the cultural heritage projects is to strongly improve the information details on the OSM map.

The OSM Sabbioneta map (in January 2018) is very poor with only few building features, so it was proposed an import process of the building features extracted from the municipal topographic map.

Schedule

The Municipality of Sabbioneta released a written permission in December 2017 stating it allows works derived from the "Carta Tecnica Comunale" to be distributed under the ODbL. The aim is to upload the building data by the end of the February 2018.

Import Data

Background

Data source site: material not available online

Data license:  not explicit (owned by the municipality of Sabbioneta)

Type of license: written permission from Municipality of Sabbioneta 

ODbL Compliance verified: Municipality of Sabbioneta has agreed to license derived data under the ODbL. 

Link to permission: Written permission from the Municipality of Sabbioneta

Community Buy-in

This import has been discussed on the Italian OSM mailing list.

Import Type

This is a one-time import. The dataset will be uploaded as a single changeset without using an automated script. All the tags will be entered manually and the dataset will be uploaded using JOSM.

Data Preparation

Data conversion

• The original cartographic data were dxf files in a Gauss-Boaga projections (western zone);

• The building features, the elevation points to the ground and to the top of buildings were extracted from the dxf files and converted to a shp file using QGIS;
• Shp file has been converted into the ETRS89-ETRF2000 geographical system ("comparable" to WGS84 World Geodetic System) through the coordinate conversion service of Geoportale Nazionale (National Geoportal);
• The elevation point data have been attributed to building polygons through a spatial join process into a GIS software context;
• Geometrical verification of the geometries and the heights obtained from the difference between the elevation points to the ground and to the top of building;
• Topology verification was carried out both in a GIS software (QGIS with the Topology Checker Plugin) and in Josm.

Tagging plan

I manually added the fields to the shp corresponding to the OSM tags and the values choices in the Map feature wiki page:

• "building" used to defined the functional typologies of the buildings: "church"; "cowshed"; "farm"; "farm_auxiliary"; "garages"; "industrial"; "public"; "residential"; "school"; "service"; "synagogue"; "transformer_tower"; "warehouse";
• For the ancillary buildings and those buildings which the function could not be defined have been used the generic value "yes";
• "man_made" with the specific tag "tower:type" used to map the bell towers ("tower" and "bell_tower");
• "barrier" used to map the historic wall of the city ("barrier=city_wall" in combination with "historic=citywalls") and the simple walls along a boundary ("barrier=wall");
• "height" defined for all the features;
• Other tags (“amenity”, “historic”, “name”, “religion”, “denomination”, “roof_shape”) for public and special buildings (town hall, theatre, monuments, etc.).

Changeset Tags

Changeset will be tagged with source=Comune di Sabbioneta - Carta Tecnica Comunale

Data Transformation Results

OSM XML file: https://www.dropbox.com/s/o209yx8ioivln5w/IMPORT_SABBIONETA_FASE1.zip?dl=0

Data Merge Workflow

Team Approach

This will be a solo effort. Import will be managed by Giorgio Limonta

The account GiorgioL-import has been created to upload the imported data.

Workflow

• Data conversion as explain in Data Preparation section;
• Open shp file in Josm through the Opendata plugin;
• Manually fix the tag name;
• Export the existing buildings and man_made features through the JOSM OverpassAPI download tool;
• Existing POI's nodes verification and possible replacement with the POI's buildings;
• Merge the tags from the existing features using the "Replace geometry" tool;
• Upload the changeset in OSM.

In case of import problem the changeset will be reverted using the JOSM Reverter Plugin.

QA

The Topology Checker QGIS Plugin and the Josm validator to prevent most problems before uploading the data. After the import, surveys and additional mapping will be carried out to improve the details and to ensure a good quality of the information.