AWMC Map Tiles

Map Tiles

February 3, 2014 in Introduction

The AWMC is proud to announce the release of a series of geographically accurate, publicly accessible map tiles, suitable for use in nearly any web mapping application or GIS software suite. These tiles are hosted on Mapbox servers courtesy of ISAW, and are created by Ryan Horne from AWMC data produced by Richard Talbert, Jeffrey Becker, Ryan Horne, Ross Twele, Audrey Jo, Ray Belanger, Steve Burges, Luke Hagemann, Ashley Lee, and others.

The area surrounding Miletus with different water levels based on time period

Offering the first (and at the time of this writing, only) geographically accurate base map of the ancient world, the AWMC tiles conform to the broad periodization presented in the Barrington Atlas, with different selectable water levels for the Archaic, Classical, Hellenistic, Roman, and Late Antique Periods. In addition, we also model inland water, rivers, and other geographical features as they appeared in antiquity. The base tiles are culturally agnostic, allowing them to be used to represent the physical environment of nearly any ancient society in the Mediterranean world. In addition to the base map and geographical tiles we also present the Roman road network, generally following the Barrington Atlas with additional work by the AWMC. Like all of our other electronic offerings, our contribution to these tiles are released under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. For detailed information on how to use these tiles in an application, please visit: http://awmc.unc.edu/wordpress/tiles/map-tile-information

These tiles are a “living” data set, and will be constantly refined to reflect the ongoing work of the AWMC, including the introduction of entirely new tile sets. We welcome feedback on any aspect of this work and we encourage the community to suggest enhancements, fixes, or any other comments.

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by Ryan Horne

OSM data updates

March 11, 2014 in ongoing work

As we have now launched our map tiles at the scale of the Barrington Atlas (the majority of which is at 1: 1 million and 1: 5 million scale), we are now moving on to update and refine our offerings with data from OpenStreetMap (OSM) along with satellite data from OSM and Google.

OSM coastline in Red; Current coastline in black

OSM vs. Current coastlines and rivers

We start by identifying features where OSM and satellite imagery provide a smaller scale and more precise representation of geography than what we currently offer, as seen in the screenshots on the right. We then consult the Barrington Atlas and other information sources to see if there are any significant changes from the ancient world to the present, and then adjust the data accordingly to conform both to visible geography and to the work of the center. This includes removing docks, modern terrain changes, dams, river course changes, etc. In addition to more precise representations of actual geography, such work will also allow us to assign OSM IDs to our features, presenting further opportunities to exploit linked data principles in our data set. These feature changes will also be added to the AWMC API, which provides stable URIs for each feature. As with all of our offerings, Pleiades IDs will also be linked to each feature where appropriate, which will eventually filter into the Pelagios network.

We are beginning the process in Crete, and we will push the results to the public tiles as soon as they are finished. As this is a painstaking process, it will be some time before we cover the entire Mediterranean world. One difficulty is the adjustment of both the coastline and water tiles from their raw OSM forms – we may offer the openwater overlays first, and then update our coastlines once that phase of the project is completed. This will also allow us to roughly define seas, bays, and other water features and therefore provide more complex geometry beyond a representative centroid for such features.

As usual, we welcome comments and suggestions on this work.

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by admin

Coast Outline Update

February 4, 2014 in Tile Update

The Coast Outline tiles now differentiate between approximate and certain shorelines in addition to period colorization following the Barrington Atlas.

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