MOvEIT

A road network for Late Antique Egypt by LAD & PAThs

MOvEIT is an open-access, collaborative road network that links the archaeological sites published in the Archaeological Atlas of Coptic Literature by PAThs.

Since the Atlas is being updated continually, so is this graph; therefore frequent changes in the next months/years might occur, as new sites are added to the Atlas.

Changes are triggered also by the adding of new connecetions between already known sites, due to advancement in studies or deeper analysis of the available sources. This document will try to keep record of these changes.

Credits

MOvEIT is a project developed by LAD: Digital Archaeology Lab at Sapienza for PAThs. The application has been developed by Julian Bogdani and the road graph has been built by Julian Bogdani and Paolo Rosati. The name MOvEIT has breen creatd by Domizia D'Erasmo.

How does it work

The application calculates the cost of movement from one site (i.e. node of the graph) to the another. The cost is calculated in terms of distance, i.e. the longer is the distance to cover, the higher is the cost of the movement. A second element is added to the calculation, based on the type of the road. A first proposal to differently weight paths assumes the following values as additional cost multiplier: - channel, rivers and sea routes: 0.8 - sea routes: 1 - coastal roads and internal valley roads: 1 - desert paths: 2

These parameters are coded in typeWeights.js. Feel free to change the muplitplying coefficients at your need.

Graphically view and calculate paths

The road graph is available as a Single-page application built using open-source libraries, such as: - Leaflet.js as a Web mapping library, - GeoJSON Path Finder as a tool for routing/path finding using GeoJSON as input.

The selection of starting and destination point for route calculations can be perfomed from drop-down menus or directly from the map, by clicking on each available point. The calculated path will be drawn on the map and a pop-up will also display information on the overall calculated distance.

Test the graph

To test the graph (and you should test if after each update and before each deploying) a specific piece of software has been built is available. You need to have available in your system in advance Node.js and Git.

To setup the environment follow these few steps, using a shell: - Clone the repository (if not already available in your local filesystem):
git clone https://github.com/paths-erc/moveit.git - Change directory to the newly downloaded folder:
cd moveit - Download ad install Node.js dependencies:
npm install - Run the test:
npm test

The test will, recursively, try to calculate paths from each available node (i.e. site, the list of the sites will be downloaded from PAThs central database) to each other available node and this procedure might take quite a long time (many hours). Errors will be printed in real time and also after the procedure finishes.

Enhance the graph

The road graph is available in this repository in the data directory where the graph.gpkg file is maintained. The Geopackage contains both the road graph and the QGIS project where alla data are already loaded. The project integrates also a model named export-road-graph that can be used to transform the road graph from the Geopackage format to GeoJSON, and performin few in-between transformations: - it converts multiplart to singlepart geometries, - then it explodes polylines to lines, - and finally saves the output as GeoJSON (edit the destination path to meet your needs).

The final GeoJSON file must be saved as src/geojson/arcs.geojson.

Before pubblication, testing the newly created graph is strongly encouraged (se above).

Finally, data are ready to be built and deployed. A local preview of the application can be run locally by typing: npm run serve and the final build can be run by typing npm run pack. node_modules and src folders are necessary only for development and you do not need to upload them on the production server.

Structure of the graph

Each connection between two points of the graph – i.e. each arc – is represented by a polyline. Each feature is associated by the following information: - name: name of the road or of the channel, if known - source: source of the information, it might be PAThs, AWMC or Satellite - operator: name of the person who digitized the feature - date: digitization date - type: type of the feature. It might be a channel, a coast road, a desert path, a river connection, a sea connection or null.

Future development

Other elements can be added to the calculation of the cost, such as the slope analysis and the presence of objective difficulties in the itinerary, such as water streams. These ‘penalties’ might be weighted as positive costs, while the presence of bridges might be considered as a negative cost. Obstacles and facilities might be added by a variety of sources, such as historical cartography or literary and archaeological sources.

Finally, some development will be done in the next weeks towards a higher degree of abstraction of the entire application, making it possible to use it with another road-graph. Some work is being done in documenting the graph production steps, in order to facilitate the reuse of this code for totally different contexts.

Zenodo

MOvEIT is deposited for long term preservation in Zenodo