2018 – Landscape Archaeology

Topophilia and the emergence of prehistoric sanctuaries: an example from Istria, Croatia

Published in: J. Wilczek, A. Cannot, T. Le Cozanet, J. Remy (eds.) Interdisciplinarité et nouvelles approches dans les recherches sur l'âge du Fer. / Interdisciplinarity and New Approaches in the…

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Some thoughts on hillshade models for Lidar analysis

Hillshade modelling is a standard form of terrain representation in cartography. The idea is to simulate lighting of a terrain from a certain direction (or multiple directions). The method is…

QGIS plugins

Depth below horizon: new (old) functionality for QGIS viewshed analysis

The basic idea of visibility analysis is to test whether particular locations are theoretically observable from a given observer point (« theoretically » because our data and algorithms can never…

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Installing Python packages in QGIS 3 (for Windows)

Python is in the heart of QGIS (or in the guts if you prefer), which enables us to use tons of third party Python libraries. In Linux systems, QGIS will…

QGIS plugins

Visibility analysis for QGIS 3.0 : tackling big data

Viewshed plugin for QGIS is based on Numpy library for handling raster data. Numpy is tuned for high performance and is (relatively) easy to use. However, it relies heavily on…

Spatial analysis & GIS

Land visibility in the Mediterranean: a large scale model

Visibility of land was a major consideration for ancient seafaring, for reasons of navigation and security. Even if the open sea travel must have been practised already by the Neolithic…

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Natural places and archaeology

First time I heard of something like “natural places” was some ten years ago at a conference in Slovenia. Several, mostly young researchers were proud to demonstrate an existence of…

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Lissage du modèle numérique de terrain BD ALTI

Le problème n’est pas nouveau, mais on ne trouve toujours pas de solutions simples pour le « maquillage » du modèle numérique de terrain (MNT) très couramment utilisé en France,…

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Benchmarking viewshed algorithm: Nuraghi of Sardinia

The new viewshed plugin for QGIS 3 features an improved algorithm which should result in perceptible improvements in terms of efficiency. So let’s give it a try! Nuraghe in Toralba-Sant'Antine…

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Looping through numpy arrays (e.g. moving/rolling window)

Numpy is the cornerstone of matrix based calculations in QGIS (and elsewhere). It does wonders with raster data (unless it hits the limit of available live memory…). A recurrent problem…