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
 

INSPIRE

Identification

File identifier
f88e75b3-07ca-4203-8951-95fd5979814c   XML
Hierarchy level
Dataset
Online resource
Protocol
file for download
Protocol
OGC:WMS
Resource identifier
code
f88e75b3-07ca-4203-8951-95fd5979814c
Metadata language
English
Spatial representation type
Vector
Encoding
Format
ESRI Shapefile
Version
1.0
Projection
code
2154
 

Classification of data and services

Topic category
  • Location
 

Classification of data and services

Coupled resource
Coupled resource
 
 

Classification of data and services

Coupled resource
Coupled resource
 
 

Keywords

General ( Theme )
  • history
GEMET - INSPIRE themes, version 1.0 ( Theme )
GEMET - Concepts ( Theme )
GCMD Keywords viewer ( Theme )
TETIS Thesaurus, version 1.0 21112019 ( Theme )
Other keywords
 
 

Geographic coverage

N
S
E
W


 

Temporal reference

Temporal extent
Begin
1747-01-01T00:00:00Z
End
1790-12-31T00:00:00Z
Temporal extent
Date ( Revision )
2022-05-17T19:08:48
 

Quality and validity

Lineage
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.
Denominator
100000
 

Conformity

Conformity
Conformity
 

Conformity

Conformity
Conformity
Explanation
some explanation about the conformance
Explanation
See the referenced specification
Explanation
See the referenced specification
 

Restrictions on access and use

 

Restrictions on access and use

 

Responsible organization (s)

Contact for the resource
Organisation name
IGN - COGIT
Email
julien.perret@ign.fr
 

Responsible organization (s)

Contact for the resource
Organisation name
IGN - COGIT
Email
julien.perret@ign.fr
 

Metadata information

Contact for the metadata
Organisation name
AgroParisTech - TETIS
Email
vincent.delbar@agroparistech.fr
Organisation name
IGN - COGIT
Email
julien.perret@ign.fr
Organisation name
AgroParisTech - TETIS
Email
vincent.delbar@agroparistech.fr
Date stamp
2022-05-17T19:26:34
Metadata language
English
Character set
UTF8
 
 

SDS

Conformance class 1: invocable

Access Point URL
Endpoint URL
Technical specification
 

Conformance class 2: interoperable

Coordinate reference system
 
Quality of Service
 
Access constraints
Limitation
 
Use constraints
Limitation
 
Responsible custodian
Contact for the resource
 
 

Conformance class 3: harmonized

 
 

  Overviews

Cassini Roads

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  Associated resources

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