Between 2006 and 2010, Eric Grosso, from the ALPAGE team, produced the beta version of the MorphAL software (version 0.1), a tool for carrying out morphological analyses using vector data, whether historical or not. MorphAL was used in ALPAGE to carry out the first morphological analyses of Parisian land parcels using vector data from Vasserot plans.
MorphAL was designed as a plug-in for OpenJUMP free software. The MorphAL documentation (version 0.1) describes in detail the functionalities available in 2011. Then, the Projects Time Machine consortium, which develops spatial analysis tools, made MorphAL available for QGis, via a toolbox in the form of a QGIS plugin.
In 2024, Eric Grosso and Eric Mermet, as part of the ANR project PARCEDES, took over the code and produced a new version (version 2.0) of the MorphAL plugin for QGIS. It was officially presented in July 2024 at the ANR PARCEDES summer school. The plugin is directly available in the QGIS extension manager, and provides new morphological indicators: Gravelius, elongation, convexity defect, compactness, etc. Documentation will be available shortly.
Precise description of MorphAL :
The MorphAL (Morphological Analysis) plugin enhances vector shapefile data of the ‘parcel’ type to make it easier to identify the structuring logic of the landscape. It adds semantic attributes to segment and polygon data concerning their geometric properties (orientation, rectangularity, convexity). These attributes correspond to mathematical indicators that are automatically calculated and included in the attribute table of the shapefiles.
The plugin can then add the orientation of each segment: researchers can then test or identify certain orientations that structure all or part of an area, and which are therefore more or less morphogenetic (for example, Roman centuriations that organise the Padana plain of northern Italy even more today than in ancient times).
In addition, the geometry of polygon parcel data can be characterised according to two morphological analysis criteria: rectangularity (parcels very far from or very close to their minimum enclosing rectangle) and convexity (parcels very far from or very close to their convex envelope). Mathematical indicators, with a value between 0 and 1, are automatically calculated and integrated into the attributes of the shapefile data, which can then be classified. The concentration of very rectangular plots in one place suggests a regularity that the historian must then analyse: it enables us to identify initial planning (for example a housing estate in ancient times, including protohistoric times) and the updating of this regular shape over time in different periods (ancient, medieval, modern, etc.). The concentration in one place of plots with a high degree of convexity suggests conflicts of form and makes it possible to identify temporal shifts that are reflected in the inadequacy of inherited spatial structures.
Bibliography :
Sandrine Robert, Hélène Noizet, Eric Grosso, Pascal Chareille, « Éléments d’analyses morphologiques du parcellaire ancien de Paris », dans H. Noizet, B. Bove, L. Costa (dir.), Paris de parcelles en pixels. Analyse géomatique de l’espace parisien médiéval et moderne, 2013, Paris, France, éd. Presses universitaires de Vincennes, p. 197-221.
Eric Grosso, Hélène Noizet, Sandrine Robert, Pascal Chareille, « The ALPAGE historical GIS: a new tool allowing a new look at medieval Paris », dans François Djindjian, Sandrine Robert (éd.), Understanding Landscapes, from discovery to Land their spatial organization, British Archeological Reports International Series 2541, Proceedings of the XVI World Congress of the International Union of Prehistoric and Protohistoric Sciences (Florianopolis, Brazil, 4-10 September 2011), 4, 2013, p. 77-86.