The 18th century Cassini roads

The evolution of infrastructure networks such as roads and streets are of utmost importance to understand the evolution of urban systems. However, datasets describing these spatial objects are rare and sparse. The database presented here represents the road network at the french national level described in the historical map of Cassini in the 18th century. The digitalization of this historical map is based on a collaborative platform methodology that we describe in detail. These data can be used for a variety of interdisciplinary studies, covering multiple spatial resolutions and ranging from history, geography, urban economics to the science of network. (2015-01-15)
 
Citation proposal
. The 18th century Cassini roads. https://idg-tetis.teledetection.fr/geonetwork/srv/api/records/f88e75b3-07ca-4203-8951-95fd5979814c
 

Identification

Data identification

Citation

Date ( Revision )
2022-05-17T19:08:48
Edition
1.0
Edition date
2015-01-01
Identifier
f88e75b3-07ca-4203-8951-95fd5979814c

  Principal investigator

Purpose
L'objectif de ce projet était de fournir des elements objectifs destinés à aider les décideurs dans la mise en place de mesures de conservation
Status
Completed

  Principal investigator

Maintenance and update frequency
Not planned
General ( Theme )
  • history
GEMET - INSPIRE themes, version 1.0 ( Theme )
GEMET - Concepts ( Theme )
GCMD Keywords viewer ( Theme )
TETIS Thesaurus, version 1.0 21112019 ( Theme )

Legal constraints

Use limitation
This work is licensed under a Creative Commons Attribution 4.0 License (CC BY 4.0, https://creativecommons.org/licenses/by/4.0 ).
Access constraints
License
Use constraints
License

Security constraints

Classification
Unclassified
User note
unclassified
Classification system
no classification in particular
Handling description
description
Spatial representation type
Vector
Denominator
100000
Metadata language
English
Character set
UTF8
Topic category
  • Location

Extent

N
S
E
W


Begin date
1747-01-01T00:00:00Z
End date
1790-12-31T00:00:00Z
Supplemental Information
some additional information
 

Distribution

Distribution

Distribution format
  • ESRI Shapefile (1.0 )

Digital transfer options

OnLine resource
Cassini Roads vector layer  
OnLine resource
france_cassini_roads_4326  

WMS Service

 

Quality

Data quality

Hierarchy level
Dataset

Conformance result

Citation

Alternate title
This is is some data quality check report
Date ( Publication )
2022-05-17T19:08:48
Explanation
some explanation about the conformance
Pass
true

Conformance result

Citation

Date ( Publication )
2010-12-08T12:00:00
Explanation
See the referenced specification
Pass
true

Conformance result

Citation

Date ( Publication )
2008-12-04T12:00:00
Explanation
See the referenced specification
Pass
true
Statement
The digitization of the Cassini maps and, in particular, of its road network, was achieved in a collaborative way using a shared PostgreSQL database and its spatial extension PostGIS. GIS editing tools such as Quantum GIS were used to remotely digitize the objects using a WMTS (Web Tile Map Service) layer provided by IGN as background. Details on the methods used to produce the georeferenced map are available on a dedicated website. This way, several operators have been able to digitize data simultaneously on the same database. In order to provide consistent data records, data specifications were proposed as a result of an important collaborative work. Nevertheless, as the specifications were enhanced during the digitization process, local variations in the capture of several attributes might be found (the attribute ‘bordered’ was added after a few months of digitization for instance). Further work will focus on the consistency of the data (both for attributes and geometries).An important aspect of the Cassini dataset is the fact that the Cassini map was not homogeneously drawn (different sheets might show different levels of detail as seen in Fig. 2) or conceived as a road map. Hence, one has to be careful when studying the road network extracted from it. Specifically, the road network inside most cities was not drawn in the map. An automatic process is therefore proposed to create so-called ‘fictive’ edges inside cities allowing to link all roads leading them. As shown in Fig. 3, a node representing the city is created at its centroid (or rather at the centroid of the geometry representing its boundary in the map) and edges are created to connect this node to the edges ending in the city. Furthermore, in order to speed up the digitizing process, some roads have been captured as continuous strokes rather than by topological road segments: some users digitized entire roads instead of stopping the capture at each road intersection. We therefore use the PostGIS topology engine to convert the digitized strokes into a topological network. This process uses a distance threshold to merge points closer than the given threshold and thus allows for the correction of minor shifts between points and a second threshold for to collect all nodes in the neighboorhood of a city. The thresholds used in the current export are 10 and 20 meters respectively. The digitized roads and cities are also provided in the export and the code for the topological export is available.
 

Ref. system

Reference system identifier
EPSG / 2154
 

Metadata

Metadata

File identifier
f88e75b3-07ca-4203-8951-95fd5979814c   XML
Metadata language
English
Character set
UTF8
Hierarchy level
Dataset
Date stamp
2022-05-17T19:26:34
Metadata standard name
ISO 19115:2003/19139
Metadata standard version
1.0

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  Principal investigator

  Publisher

 
 

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Cassini Roads

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