The Geospatial Network Model of the Ottoman World

The Geospatial Network Model of the Ottoman World aims to reconstruct the time cost and financial expense associated with different types of travel in the Ottoman Empire.

Our model will illustrate network of cities, roads, rivers and sea lanes that framed movement across the Ottoman Empire. It broadly reflects physical conditions around the eighteenth and nineteenth centuries.

“Ottoman Routes Map”, housed in Ottoman Imperial Archives in Istanbul, is spatially analyzed for this project. The map was created in 1892 by the “Erkan-ı Harbiye Dairesi Dördüncü Şubesi” in Istanbul. It originally aims at showing the distance between Ottoman settlements in hours.  

The process of digitalization and spatial analysis of the map has several steps:

First, map sheets are digitally joined by rubber-sheeting the seams and other errors.

Next, historical map was georeferenced.

The map is converted from raster data (image) to vector data (coordinated map). Georeferencing was done in ArcGIS software by matching a significant number of control points from the historical map and the base map. With this process, historical map, which was an image without coordinates, became a map with coordinates and it is located on its real place on the earth.

After that, the gazetteer points were projected as a new layer on the map.

Gazetteer points are derived from the historical gazetteer prepared for our project, which is primarily based on the Ali Pasha Collection of Papers at the Gennadius Library Archives. This step enables us to visually observe Ali Pasha’s sites of influence and also provides a guide to match historical place names on the map.

Following that, place names on the historical map are digitally marked on another map layer and matched with the gazetteer points when they are present.

This step also includes a meticulous work of transliteration of Ottoman toponyms and locating them after a bibliographical research. An attribute table was prepared for this layer which presents the historical name, present-day name, historical administrative unit, latitude, longitude and gazetteer match ID of each place.

Finally, the routes connecting the settlements (as they are shown in the historical map) are digitally drawn on another map layer.

Hours of distance is added to this layer.

This ongoing project started with the spatial analysis of the Balkan and Western Anatolia territories and will continue with other parts of the empire.