مکان یابی و تبیین ساختار کالبدی شهر باستانی شاپور خواست برمبنای الگوی شهرهای ساسانی با ‏استفاده از ‏GIS‏ ‏

After the falling of Parthian dynasty done by Ardeshir Babakan, in the first decades of Christian century, a new emperor named Sassanid originated. Historical sources show that the first Sassanid kings were the founders of the great cities. Ardeshir and Shapur I began to develop ancient cities and build new towns. At that time, the ancient cities of western Iran were centers for industrial production and trade, as well as for the establishment of security of Royal Routes. One of these cities called Shapur-khast was founded by Shapur I. The main monumental buildings remained of it are the Castle of Shapur-Khast and Shapuri bridge. Shapur-Khast castle was as the governing castle called as Falak al-Aflak castle. The location of this city is considered to be one of the most important cities in the west of the east (Kermanshah to Isfahan) and north-south (Shush in Hamadan), both in terms of military strategy and exploitation of natural and geographical complications and in terms of communication status. The question we will address in this article is how to select the Shapur-khast Template for Sassanian designers? The purpose of this study is to execute the location of the city and adapting the form of city with the Sassanid architects design patterns in Shapur I ancient era.
Keywords: Shapur-Khast, Ancient Pattern of Cities, Sassanid Cities, Location Choice, GIS.
 
Introduction
On Shapur-Khast city location based on historic script and folk narrations about the fortress Shapur-Khast and Shapouri Bridge, two other locations near Khorramabad, Saboor and also Masur Hill, can be mentioned; But the Sabour hill is not such that it can be considered a remnant of a city, and the Masoreh Hill also lacks the evidence of urban architecture belonging to the Sassanid era and early Islamic. However, the existence of a script on the Shari’ati Street of Khorramabad as an archaeological document shows that the location of Shapur-Khast could be found at a distance far from the remained stone structures. There are remnants from the early Islamic centuries such as brick minarets, broken bridges, stone vortexes, grinding mills, as well as archaeological evidence in the Ghaziabad area to the nearby Gibri mill from an old city that accidentally carried out from of gas supply and water supply operations. It is mainly associated with the architecture of gypsum and plaster. It can be concluded that the ancient city of Shapur-Khast has been within this region. But undoubtedly, archaeological excavations in this area can help to achieve a definite result
The research method of this study in first step is interpretative historical method. Therefore, the historic and physical characteristics of city, monuments and urban archeological properties of the city analyzed. In the second step the location characteristics and geomorphological properties of the three cities which founded by Shapur I, Gundi Shapur. Bishapur studied and the properties of general slope of lands, location of city next to river, and main access way illustrated. The results show that in all three case studies the location of the city is depended on the minimum distance of the cities and riverside. Also, the main inclination of the urban lands and surroundings is gentle. Bishapur and Nishapur physical and location properties are much the same than Gundi Shapur. In Gundishapur the slope of the city has not a main role in setting the location of the city. In step 3 of research method the city plan corresponded with the Shapur I ancient cities to find the main properties of founding Sassanid urban planning. Analysis shows that the leader and king of Sassanid era lived at out of the boundaries of city and generally lived in a highland castle above or aside of city. Sassanid cities same as Achaemanian urban planning based on religious beliefs. In general, the cities have barracks and have four entrance gates to four geographical orientations. Also there was trench all around the city instead of places reach to rivers or highland mountains. These cities generally located at riverside for access to fresh water and kingdom roads for trade and commercial activities or for increase the security for the bridges or kingdom roads. Main bridges of the city located alongside or in closest access to the entrance gates of the city.
The variables to be examined for location studies include: 1. General slope of the earth to obtain the original situation of the city relative to the elevations and geographical conditions of the area, 2. Distance from the river, which is an element for water supply and a defensive indicators of the city, 3. Distance from the King roads, which is a factor in the easier connection between cities and the establishment of the security of the Shah’s ways. These three variables were analyzed in all three cities of Gundi-shapur, Bishapur and Nishapur using Arc GIS software and the results show that in the location of the three cities some indicators are permanent which one of them is trying to find the closest route to the river, in addition, the slope of their placement has a gentle slope. Bishapur and Neyshabur cities have the same slope features as Gundi-Shapur. In Gundi-Shapur city, the slope of the earth has had less impact on the city location. However, in the case of the riverside location, each city has a common feature. As a result, in order to locate the town of Shapur-Khast, it should be taken into consideration that a place with gentle slopes and distances close to the river and the road is the main features of location strategies.
In step 4 of research method, with the aim of the ArcGIS software and considering the information of archaeological excavations in the region, library studies and monumental building restored from Sassanid era in Khoram Abad the location of ancient city of Shapur khast presumed.
There are cities in the west and southwest of Iran whose foundations are attributed to the two Sassanid kingdoms Ardeshir and Shapur I. The construction of each of these cities pursued objectives that could have been placed in economic, political, military, or residential settings; the Shapur-Khast city was built along the Kingdom Road and the city formation system (the location of the city relative to geographic constraints) is connected to the mountain and riverside, same as military towns, especially Bishapur city. Using ArcGIS software and three main indicators of locating Sassanid cities applied to find a pattern for the location of three case studies this research. According to the words of historians and archaeologists who have considered the location of Shapur-Khasht in current Khorramabad, this pattern also has been considered in ArcGIS software for Khorramabad city. The analysis of GIS data, from the Sassanid era and historical texts shows that the probable location of the city of Shapur-khast located in south of Khoram Abad city in the Qazi-Abad, Hoseyn abad and hillside Madbeh to Kheyr-Abad hills and Like its neighboring cities, it has two parts; one is the headquarter and the other is Sharhistan. Considering the remains of the Shapur Castle, such as Shapour-Khast Fortress and Shapouri Bridge, the fortress of Falak Al-Aflak is the same headquarter that was built outside the city and above the cliffs overlooking the Khorramabad valley. Sharistan in located in the region of in the Shapuri Bridge, from the Kheirabad Hill Up to Qazi Abad and the area of Hussein Abad hills. It seems that the city’s pattern, like its neighboring cities, is grid shape plain, its grid networks streets that at the ends of which are the gates of the city. The Shapuri Bridge, which was built on the Khorramabad River, was almost near one of the gates of this city and allowed the west to east (Tisfoun to Shapur-Khast), and it crossed the road for traffic and control of passage ways.