تحلیل تغییرات دسترسی به خدمات بیمارستانی شهر زنجان با استفاده از روش اندازه‌گیری دسترسی مکانی بالقوه در فاصله زمانی 1385-1395

A B S T R A C T
Nowadays, the rapid increase of cities’ population and the lack of balanced development of urban services, reduces the level of citizens' use of urban facilities and services. Measuring the potential spatial accessibility index is important because equitable access to the services which is defined as spatial justice, is important for planning and allocating health resources.  Regarding the importance of health in the society, measuring the potential accessibility to the health care services at the level of hospitals is the subject of this study. To measure the accessibility, three methods of 2-Step Floating Catchment Area (2SFCA), Enhanced 2-Step Floating Catchment Area (E2SFCA) and 3-Step Floating Catchment Area (3SFCA) have been implemented in two time periods of 2006 and 2016. The basis of these first two methods are supply and demand while in the third one, the competition between the suppliers is also taken into account.  The results revealed the inequality in accessibility of both urban blocks and neighborhoods to the hospital services for two sections of study which are 2006 and 2016. On the other hand, the accessibilities were improved from 2006 to 2016 by all of the three methods’ results. There is also expected differences between the results of three methods, as the results of 3SFCA method shows the lowest accessibility in compare with the two other methods. The results of this research shows that despite of the improvement of hospital capacities in the city during ten years of study, inequality is observable across the urban blocks and neighborhoods. The strategy for reducing these inequalities and improving the spatial justice is to increase the number of hospitals or to enhance the street network in areas of poor accessibility to the hospitals.
Extended Abstract
Introduction
Considering the importance of the health issue in the society as well as the importance of timely access and delivery of the patient to medical services, this research has considered the issue of location access to hospitals in Zanjan city and by using three methods of the two-stage floating coverage area (2SFCA) , improved two-stage floating coverage area (E2SFCA) and three-stage floating coverage area (3SFCA) calculates and compares the access to hospitals at the level of city blocks in two time periods (2015 and 2015). The rapid growth of the population and the residential area in Zanjan city has caused the examination of the level of access to essential services such as hospital services in this city and especially its changes to be significant. In the calculations of the access rate, the two factors of supply and demand along with the distance factor between the two under the network play the main roles. Therefore, we are facing a geographical problem, which uses a geographic information system (GIS) to perform its calculations.
 
Methodology
In this research, the spatial accessibility index has been used to achieve spatial justice in the case of hospitals in Zanjan city. For this purpose, three methods of floating coverage are used, access to hospitals for the years 2015 and 2016 at the block level is calculated and evaluated using statistical data, spatial data and street network. It should be noted that the spatial analysis of this research has been done using ArcGIS software and using analyzes such as Topology, Network Analyst and Spatial Join along with programming with ArcPy language.
 
Results and discussion
To analyze hospital accessibility with the methods presented above, considering the important considerations of determining the floating influence area for hospitals, as well as considering the functional radius for city hospitals and most importantly, the scale of the city, in terms of population and area, the approximate coverage area. With an average speed of 50 km/h, approximately equivalent to six minutes of time under the network and using the origin-destination matrix was considered. Because the visitors to the hospital are people who have a disease or movement problem and are not in good general condition, or sometimes they need fast and emergency treatment, driving mode has been used to calculate accessibility. In the two methods of the improved two-stage floating infiltration area and the three-stage floating infiltration area, the six-minute area was divided into three sub-zones (areas) of two, four, and six minutes, so that the blocks that are outside the six-minute area have zero access and within the area to The reason for the existence of three sub-zones and giving proportional weight to them is that accessibility decreases with increasing distance. Here, the supply criterion and in other words capacity, the number of beds in each hospital is considered. These procedures were carried out for all hospitals in the city. Then based on relations 1 to 8, the ratio of supply to demand (available resources) was calculated for each hospital.
 
Conclusion
The results indicate the uneven distribution of hospital use in Zanjan city in 1985 and 1995. In addition, the three methods used also have different results, which is related to the parameters of each method. In 1985, there was a spatial disparity in the distribution of facilities in the whole city, so that according to the three-step method, the old fabric in the city center and the northwestern areas have low accessibility. In 1995, the northern area of the city, due to the high capacity of the hospital established in this area and the presence of several other hospitals in the coverage area of this hospital, has a higher accessibility, but in the south and the center of the city, the old and traditional fabric has caused an inappropriate network and access has reduced Also, in the south and center of the city and parts of the northwest, there is an inequality of access, to compensate for which, a new hospital should be established in these areas or the transportation network should be improved. In measuring access to the third method, the size of access is smaller than the other two methods due to the introduction of competition between facilities, and in fact, it moderates the overestimation of access by other methods.