Improving the Urban Planning of the Green Zones in Al- Dammam Metropolitan Area, KSA, Using Integrated GIS location-allocation and Accessibility Models

In the present study, the location-allocation and the accessibility models of GIS were integrated with the urban planning standards of the Ministry of Municipal and Rural affairs of Kingdom of Saudi Arabia (KSA) in order to enhance the spatial planning and the environmental sustainability of the green zones in Al-Dammam Metropolitan area, KSA. The integration of these models provides a framework for investigating the efficiency of the spatial distribution of the green zones and generating alternatives either by suggesting new effective service or by improving an existing one. To achieve these purposes, the accessibility within (5, 10 and 15) minutes to the service areas in the green zones that is classified into nine types (“neighborhood gardens”, “specialized parks”, “cities gardens”, “children’s gardens”, “district gardens”, “streets and squares gardens”, “sports city”, “Sports clubs” and “Playgrounds”) was analyzed through analyzing the network structure of the green zones in Al-Dammam Metropolitan area. The location-allocation model was used based on the maximum coverage within response time of no more than 10 minutes.The study revealed poor distribution of the green zones, the low per capita green zones rates with only (3.52 m/person) and there were no green zones in 45 districts representing 33.3% of the total districts in the investigated area. Consequently, Al-Dammam Metropolitan area suffers from the weakness of the green zones structure and the shortage in fulfilling the needs of population. The current needs were determined as nine services by two “sports cities”, two “sports clubs”, two “streets and Squares gardens”, one “district garden”, one “children’s garden” and one “specialized park”. It is recommended that the results of this study be taken into consideration by the decision makers while developing the urban planning strategies for improving the infrastructure efficiency as the KSA vision 2030.


Introduction
There is an increasing scientific recognition (Daniel et al.2017;Dinand and Sjerp 2017;Angela 2014;Dongkun & Hyeyeong,2011) of the importance of the functional, recreational, environmental and health roles played by the open green zones in the people's alternatives either by suggesting new effective service systems or by improving the existing service systems, this is because the local planning decisions made by government or local leaders are often far from ideal.
The application of geographic analysis in services planning has been introduced in the recent years as a highly dynamic research area . The application of the GIS accessibility and location-allocation models depends on the existence of spatial and demographic distribution in a specific manner and determining the demand locations based on specific criteria for selecting the best sites for services . The minimum impedance and maximum coverage models are regarded the most efficient models for planning the green zones services (Daskin & Dean 2004).
There is a growing interest in public urban green lands as one of the most important elements of sustainable urban planning around the world, simply because it provides important ecosystem services for urban dwellers, including recreational and sports activities.
Most studies have shown that access to urban green lands is associated with increased wellbeing, physical health and social communication (De Vries et al., 2003;Maas et al., 2006;Kondo et al., 2018;Villeneuve et al. 2012;Wood et al., 2017;Wu et al., 2015) and reduced chronic job-related stress (Herrera et al.2018). In addition, urban green lands can support biodiversity (Strohbach et al., 2009;Dallimer et al., 2012), support a range of benefits known as ecosystem services (Tratalos et al.2007;Bolund & Hunhammar, 1999), and mitigate the effects of urban heat island (Onishi et al., 2010).
Accessibility and location allocation were used as effective information to measure the efficiency of the spatial distribution of the transportation network and widely inequitable access to health services (Francisco et al., 2017), access to primary health care centers in Johannesburg (Hunadi, 2014), to allocate an improved site to earthquake relief centers (Bahram et al., 2018), to allocate the site to fire stations (Samira et al., 2018), spatial analysis of fire stations in India (Javaid et al., 2017), land planning (Geurs, 2004), urban planning (Zhong et al., 2016;Wei & Yang, 2016), and tourism planning (Pan & Cong 2012;Jin et al., 2010).
With regard to the application of accessibility and the allocation of sites in green areas, they were applied in the study of access to green areas of Shanghai (Fan et al., 2017), access to nearby greenery and human health (Dinand & Sjerp, 2017), and the effects of population density on the quantity and structure of green spaces (Daniel et al., 2017), accessibility analysis for nearby gardens (Muge et al., 2016), citizen comfort analysis using accessibility to green areas (Lin et al., 2019), accessibility using land suitable for public parks in Larkana (Imtiaz et al., 2011), modelling of access for older people to green areas in high-density cities (Fangyinget al.2016), and planning urban green areas environmental network (Haifeng et al., 2015).
Distance is a dominant aspect of accessibility indicators for nature or urban green lands, and the frequency of the effects of green land use decreases as the distance increases (Coombes et al., 2010). Most studies have confirmed that access to natural environments outside the home at a distance of 300 meters is associated positively with mental health indicators (Triguero-Mas et al., 2015), and in the United States the standard for walking is a mile or 400 meters at most (Sturm & Cohen, 2014).The importance of access to nearby green lands was also recognized in the policy, with the European Environment Agency recommending that green lands must be accessible within a 15-minute walk from the residents' residence (Department for Environment Food and Rural Affairs 2019).
The urban planning for the use and management of the green zones is of exceptional importance especially in cities located in hot and dry latitudes like Al-Dammam metropolitan area. The green zones are regarded one of the planning treatment methods for creating suitable and comfortable climatic conditions for the population. The nature of the desert climate, the rapid increase in the population and urbanization particularly after the petroleum discovery, the increasing air and audiovisual pollution as a result of the development of the petroleum city and the resulting increase of human activities makes the existence, management and development of the green zones a necessity in the urban environment of Al-Dammam metropolitan area.
The present study aiming to improve the spatial urban planning of the green zones at Al-Dammam metropolitan area ensures that neglecting the planning of green zones based on integrating the standards of urban planning with the accessibility and location-allocation models leads to the misuse of the green zones. This may increase the inadequacy of the environment for fulfilling the environmental climatic and recreational needs of the population besides lowering the per capita rates of the green zones in Al-Dammam metropolitan area compared to other Arabian and international cities.
Compared to the previous studies, this study is distinguished by combining two of the most effective scientific methods in the process of evaluating and planning services and green areas. These are the accessibility method in information systems and site allocation models.
This study was also distinguished from the other studies in that it applied local and international planning standards in assessing green areas. This study is also unique because it took into consideration 9 different types of green areas and did not depend only on one or two types, which gives the study a comprehensive characteristic in its handling of the topic of green areas. The previous studies also revealed the shortage of studies in the Arab library about the effective systematic integration of modern methods with geographic information systems in its handling of urban planning issues that put the green areas at the top of their priorities.
This study takes on special importance for a number of considerations, including the apparent lack of urban green lands research in the Arab regions in general and in the Saudi Arabian community in particular, unlike in the European and Northern American regions.
Therefore, there is no opportunity to compare the locations of green lands that differ. There is no study in the field of the current research subject, which is the integration of accessibility models and the allocation of location in GIS in order to improve the spatial planning of green lands. Therefore, this study is unique as one of the first studies in the Arab Library that applies. It is also noticeable that there is a section of these studies that are listed in the context of previous studies which are consistent with the researcher's study in improving the spatial planning of health services by applying accessibility models and the allocation of location in GIS.However, it was applied to areas outside the Arab region. Moreover, this helps the methodology and methods used in this study to generalize the results to Urban planning models in other similar areas, in addition to demonstrating the true importance of GIS model studies in urban planning.
This study seeks to determine the efficiency of the spatial distribution of the green zones and its compatibility with the residential neighborhoods in Al-Dammam metropolitan area. It ensures the needed functional effectiveness and suggests new services based on modern unique approach through integrating the urban planning standards with the accessibility Ashraf Abdelkarim/ GEOSI Vol 5 No 1 (2020) 1-46 models. It aims to determine the efficiency and pattern of the distribution of the green zones with its various types through several analytical and statistical GIS techniques. This study also seeks to determine the current and future needs of the different types of green zones in Al-Dammam metropolitan area using the location-allocation technique.

Area of Study
Al-Dammam metropolitan area lies in the eastern province of KSA, at the Arabian Gulf coast between the waters of the Arabian Gulf and the dunes of Ad-Dahna desert. It is located between latitudes 26° 06' N to 26° 30' N and longitudes of 49° 40' E to 50° 15' E.

Methods
This study combined the analysis of the accessibility to the green zones service areas to evaluate and to determine its coverage based on defined time intervals, with the locationallocation analysis. This also aims to plan the future of the green zones in Al-Dammam metropolitan area and determine the areas of deficiency and suggest new locations for services. GIS Network analysis is one of the most powerful tools used in this study as it is largely connected to the roads network which is the main transportation mean (ESRI, Arc GIS 2019). Other spatial and statistical analysis tools were also used for determining the green zones spatial distribution pattern.
The methodology of assessment and planning of the green zones in Al-Dammam metropolitan area has gone through five stages using the Arc GIS software (Figure4), as follows: The first stage was collecting the required data for the surface network analysis including roads layer and service locations layer and other descriptive information such as information about the road segments (distance, time required, waiting time, speed and Ashraf Abdelkarim/ GEOSI Vol 5 No 1 (2020) 1-46 direction). All the collected data were projected by the same projection system to ensure that the results and outputs have the same ground projection.
The second stage was carrying out the "topology" on the roads layer in order to solve any spatial errors.
The third stage included building the attribute table and filling specified attributes with the corresponding descriptive data to act as weights when performing the surface network analysis.
The fourth stage included building the network data-set on the roads layer with filled attribute weights after being processed against the topology errors.
The fifth stage included performing the accessibility analysis based on service area analysis to evaluate the current standings of the green zones in Al-Dammam metropolitan area and to determine the coverage of services within time intervals of 5, 10 and 15minutes.
The accessibility analysis is accessed from the network analysis toolbar in Arc GIS after activating it. The parameters of the accessibility analysis layer were defined as follows: the impedance weight attribute (distance or time), the outputs fit to the borders of the roads network layer using the "trim polygon" tool, and the output ranges merged using the "merge by default break" tool. After setting the parameters of the analysis layer and adding the layer of services locations (facilities) in the "Network Analysis Window", the output was obtained by solving the network using the "solve" tool. The output for all the administrative sections is then obtained for each section individually to determine the percentage of service coverage for each administrative section. Figure 5 illustrates the structure of the model of accessibility to the green zones in Al-Dammam metropolitan area.
The fifth stage also included performing the location-allocation analysis for planning the future of the green zones in Al-Dammam metropolitan area and for defining the areas of deficiency and suggesting new services. The location-allocation model is performed after building the roads network. It is accessed from the network analyst toolbar and it's parameters such as impedance weight attribute and value (distance or time), the number of facilities (facilities to choose), the impedance cutoff, and the location-allocation problem type. Figure 6 illustrates the structure of the location-allocation model for the green zones in Al-Dammam metropolitan area.
There are seven types of the location-allocation models (Hakimi1964), in the present study; the maximum coverage type was used (Rahman and Smith 1996) with the formula: Where (I) is the group of demand points or the time duration or the population as weight, (xᵢ) is the location-allocation parameter with either zero or one value only. After setting the parameters of the analysis layer and selecting the "maximize coverage" location-allocation type, the spatial locations of services (facilities) and the demand points were provided for the administrative sections of the study area and were represented by points layer in the Network Analysis Window.  The Network is then solved using the "solve" tool for obtaining results and suggesting new locations for services in all the administrative sections in Al-Dammam metropolitan area of study.
Various GIS spatial and statistical analysis tools were used in this study such as; geographic distribution measuring tools ("standard distance" and "directional distribution"), and proximity analysis tools ("buffer"), these tools were implemented effectively to evaluate the spatial distribution pattern of the green zones in the investigated area.
This study depended on official governmental sources for data represented by the GIS unit (Issue 101, 2019) provided by the secretariat of the KSA eastern province. Twelve digital GIS layers were obtained including; the administrative borders of the cities of the KSA eastern province, the administrative division of Al-Dammam metropolitan area, the boundaries of the neighborhoods of Al-Dammam metropolitan area, and nine different green zones layers including; Children's gardens, Neighborhoods gardens, districts gardens, cities gardens, streets and squares gardens, specialized parks (corniche), playgrounds, sports clubs, and sports cities. Maps for the urban expansion were also obtained.

Geographical Distribution of the Green Zones in Al-Dammam Metropolitan Area
Many studies (Mirchandani & Francis 1990;Marsh & Schilling 1994;Tammy 2004;Tsou et al., 2005;Tammy & Zvi, 2007) ensure that the spatial equilibrium is the main aim of the spatial expansion, this can be beneficial for social, urban and regional sustainability and to the rational share of the public welfare. Reaching the spatial equilibrium is an effective way for achieving the maximum social welfare, in some cases the geographic redistribution is the solution for correcting the misdistribution and achieving the fair equilibrium (Yasenovskiy & Hodgson 2007;Puerto et al., 2009;Ma et al.,2017;Wu et al., 2018).
From the analysis of results in (table 1) and (figure 7), it was found that the total number of the green zones in Al-Dammam metropolitan area was 697 with total area of 6.88 million square meters. There were 311 "neighborhoods gardens" representing 45% of the total number of green zones with total area of about 1.1 million m 2 . There were 214 "specialized park" representing 31% with total area of about 2.2 million m 2 . The "districts gardens" with   The number of green zones distributed over the districts of Al-Dammam metropolitan area differed due to the different demand rates. It was noticed that the green zone type with teh largest number was the "neighborhoods gardens" serving over 67 districts representing about 49.6% of the total number of districts in Al-Dammam metropolitan area. While the least frequently established green zone type was the "sports cities" serving about 3 districts only representing about 2.2%.
The geographical distribution of the green zones has been affected by the urban growth, The geographical distribution of the types of green zones was obtained using the "standard deviational ellipse" tool and showed the distribution details as follows: for the "children's gardens", the distribution direction took NW-SE axes, the ellipsoid was characterized by large size with 61.46% of the length of diameter extending from North to South. The ellipse included 87 districts representing 64.44% of the total number of districts.While, 35.56% of the districts fell outside the ellipse. Regarding the services of ("neighborhoods gardens", "districts gardens", "city gardens", "streets and squares gardens", "specialized parks (cornice)", "playgrounds", "sports clubs", and "sports cities"), the distribution direction took N-S (north-south) direction and the ellipsoid was characterized by its small sizes with lengths ranging from 24.24 to 69.47% of the length of the diameter extending NW-SE (northwest-southwest). From the analysis of the "mean center" results, it was found that the mean geographic center of the ("children's gardens", "neighborhoods gardens", "district gardens", "city garden", and "specialized parks") services lie in Gharb Al-Dhahran district; while, for the "streets and squares gardens", the geographic center lied in the Hagr district; for the "playgrounds", it lied in AbdallahFouad district; for the "sports clubs", it lied in the sports city district; and for the "sports cities", it lied in Al Hussam district.
From the analysis of the "average nearest neighbor distance" results, it was noticable that the spatial distribution of the green zones had a "clustered pattern" with value of (0.45) and zvalue of (-27.65) which was lower than the critical value of z-parameter. For the types of green zones of ("children's gardens", "neighborhoods gardens", "districts gardens", "specialized parks", and "sports clubs"), the pattern of distribution was "clustered patterns" with values ranging from (0.28 to 0.49) and Z-values ranging from -6.63 to 19.93.
While, the green zones types of ("cities gardens", "streets and squares gardens", and "playgrounds") were found to have "random patterns" of distribution with values ranging from (1.02 to 1.28) and z-values from (0.11 to 1.52). The distribution pattern of the "sports city" type of green zones was found to be a "dispersed pattern" with value of (3.51) and zvalue of (8.33) (figure 10). Determining the efficiency and adequacy of the spatial distribution of the green zones is a very important element of the contemporary urban planning (Castella et al., 2005), which gained enormous benefits from the modern techniques, especially, the GIS spatial and statistical analysis tools. This comes for ensuring the ease of accessibility to the green zones through selecting (allocating) the optimal locations and through the fair distribution of these zones (Ohta et al., 2007;Howerton, 2006;Zhu et al., 2005). The optimal traffic rates an area of focus to the planners, geographers and decision-makers; this reflects the importance of the

This study is based on the standards set by the KSA Ministry of Municipal and Rural
Affairs for evaluating the efficiency and planning the current and future needs of green zones in Al-Dammam metropolitan area. Therefore, the results of study were introduced to the decision-makers (table 2). Reviewing the current standings of the per capita rates of the green zones in Al-Dammam metropolitan area (figure11)and (table 3), it was found that the rate was 3.52 m 2 / person. This rate was lower than the standard rate of 5.9 m 2 / person determined by the Ministry of Municipal and Rural Affairs of KSA. At the cities level; it was found that the per capita rates of the green zones in Al-Dammam city was 3.15 m 2 /person. While, for Al-Khobar city, it was 4.21 m 2 /person, and for Al-Dhahran city, it was 3.03 m 2 /person. It was clear that in Al-Dammam and Al-Dhahran cities, the rates were obviously lower than the standard rate, while in Al-Khobar city, it was fairly compatible with the planning standard rate. By applying the GIS "buffer" technique to evaluate the effectiveness of the green zones types; it was found that; using 250m buffer for the "neighborhoods gardens", about 47% of the districts fell outside the 800m effective buffer of the "districts gardens" (figure12), 87% of the districts fell outside the 275m effective buffer of the "children's gardens", 44% of the districts fell outside the 5,000m effective buffer of the "specialized parks" (figure13), 81% of the districts were outside the 1,000m effective buffer of the "streets and squares gardens", 81% of the districts were outside the 500m effective buffer of the "cities gardens" (figure14), 84% of the districts were outside the 500m effective buffer of the "sports clubs", and 24% of the districts were outside the 10,000 m effective buffer of the "sports cities" (figure15).     The reasons behind the low rate of access to the green areas of these neighborhoods was due to its distance from the old nucleus of Dammam metropolis, which were completed by many services, facilities and infrastructure, and the poor road network in addition to the distance from the facade of the Nile Corniche, which wasattracted by many green areas services.
There was a reflection of many of the factors that influenced the map of the green areas in urban area, which came at the head of the distribution and density of the population, the age and modernity of the neighborhoods, the area and location of the neighborhoods, modern urban extensions, transportation and transportation, private sector participation, and retail planning of secretariats.

Future of the Green Zones
The location-allocation model was regarded a very powerful tool for planning the public utilities to find the best locations for facilities to ensure the maximum benefit and the fair sharing of services. Its applications was previously limited because of data unavailability.
However, currently there are existing "land information systems" in many cities providing the required data and parameters for the location-allocation model. Achieving the spatial equilibrium of the green zones in Al-Dammam metropolitan area through allocating locations for the green zones services is an effective planning approach for maximizing the social welfare and improving the spatial planning of the green zones. The GIS-based locationallocation model allows generating planning alternatives either by suggesting an effective service or by improving an existing one.
In the present study, the "maximum coverage" location-allocation model was applied with response time of no more than 10 minutes. The results were as follows: within response time of 10 minutes, the "sports city" service covered 105 districts representing 77.8% of the total 135 districts in Al-Dammam metropolitan area. The covered (serviced) districts by the "sports city" service were found to be located in the central and northern parts of Al-Dammam metropolitan area. To ensure all the districts are covered by this service, two "sports cities" are suggested to be allocated, one in the north western part of Al-Dammam metropolitan area and the other one in the southern part. Within response time of 10 minutes, the "sports clubs" service covered 123 districts representing 91.1% of the total 135 districts.
The covered districts by the "sports clubs" service were found to be located in the central and northern parts of Al-Dammam metropolitan area. To ensure all the districts are covered by this service, two "sports clubs" are suggested to be allocated, one in the north western part of the area and the other one in the southern part (figure 21).
Within 10 minutes response time, the "streets and squares gardens" service covered 128 districts representing 94.8%, these districts were found to be covering all Al-Dammam metropolitan area except the northwestern and southern parts of the area. To cover all the districts by this service, two "streets and squares gardens" are suggested to be allocated in the missing parts of the area. Within 10 minutes response time, the "cities gardens" service covered 127 districts representing 94.1% of the total 135 districts of Al-Dammam metropolitan area; these districts were found to be covering all area except of the northwestern part of the area. Consequently, one "city garden" is suggested to be allocated in the northwestern part of the area (figure22).
Within 10 minutes response time; the "children's gardens" service covered 134 out of the 135 districts representing 99.3%, the missing district was found to be located in the northwestern part of the area. Consequently, one "children's garden" is suggested to be allocated in this part of the area. Within 10 minutes response time; the "specialized parks" service covered 125 districts representing 92.6% of the total number of districts in the study area; the covered districts were found to be located in the northern and eastern parts of the investigated area. Hence, one "specialized park" is suggested to be allocated in the northwestern part of the area as this part is not currently covered by this service. It was also found that, all the 135 districts of Al-Dammam metropolitan area were covered by the services of "districts gardens" and "neighborhoods gardens" within the defined 10 minutes

Recommendations
The recreational services provided by the green zones are regarded the main development elements in Al-Dammam metropolitan area. Any deficiency either in the type, quantity or spatial distribution is a strong limitation of the sustainable urban development.
The current increasing population rates, the urban expansion, and the increasing regional, functional, and administrative roles of Al-Dammam metropolitan area puts extra lodes on the urban planning of the area. In addition, the lower per capita rates of green zones in Al-Dammam metropolitan area and the deficiency of coverage and accessibility to all the services of green zones during the defined 5, 10, and 15 minutes time to the service. This gives a negative effect and poses a great challenge for the green sustainability and the recreational activities.
This study recommends the redistribution of the green zones regularly based on the density and needs of population in all the districts of Al-Dammam metropolitan area. This requires fulfilling the current deficiencies of green zones that are estimated in this study by nine green zones services, i.e. two "sports cities", two "sports clubs", two "streets and squares gardens", one "district garden", one "children's garden", and one "specialized park".
It is also recommended that the area of the green zones should be increased to raise the per capita rates to meet the planning standards of the Ministry of Municipal and Rural affairs of KSA.
Attention should be paid to the unused 40 km long waterfronts through the establishment of some recreational facilities such as gardens, parks, and high class restaurants. These waterfronts can be also better used through building terraces, planting them, providing seating places and ensuring regular cleaning and maintenance. The recreational areas should be provided with other services and facilities to form the so-called "combined services areas" in the form of hierarchy. These combined services areas should be planned as planning units divided according to the density of population and the demand on the services. This will raise the efficiency, decrease the supply cost and make it easy for the public to deal with these services.
This study recommends the need to increase the availability of toilets in the gardens and permanent maintenance of them, with the need for the presence of cleanersto work continuously to maintain children's toys in the gardens, with increased signage and placement in each corner of the gardens, with the need to install waste baskets commensurated with the nature of the areas green gardens. Some the industrial uses have become within the urban cluster; therefore, there is a need to turn them into green areas to improve the urban environment of the present.
This study also recommends activating the social partnership between both the public and private sectors through exchanging opinions and views for improving the efficiency of the green zones services. The governmental support to the private sector is also preferred for improving the green zones and facilitating regular continuous maintenance of its services and providing the most up to date services with modern techniques as the needs of the population in Al-Dammam metropolitan area.
Finally, it is also strongly recommended taking into consideration the factors of ease of accessibility to public services together with the urban planning standards and the GIS spatial and statistical analysis techniques while planning and/or evaluating the green zones in cities (i.e. the methodology of this study is recommended to be applied on similar green zones in other cities).

Conclusion
The population growth, urban expansion, and the rapid growth of civilization attributed to the petroleum discovery in Al-Dammam metropolitan area yielded a negative effect on the urban environment in the area. The lower per capita rates of green zones that differs from one district to another makes it a necessity to reconsider the planning and distribution of the green zones, especially with the current spatial expansion and the increasing land prices that led to the existence of some other types of land-use in areas previously planned to be allocated for green zones. Therefore, increasing the area of the green zones became a necessity for achieving the sustainable environmental equilibrium in Al-Dammam metropolitan area.
This study combined the GIS accessibility and location-allocation models with the urban planning standards of the Ministry of Municipal and Rural affairs of KSA for improving the spatial planning of the green zones in Al-Dammam metropolitan area. Using the Accessibility models only allows the evaluation of the current services provided by the green zones, but, it is not capable of suggesting new locations for services or reallocation of existing services.
Therefore, there is a need to integrate accessibility analysis into the location-allocation model.
The results of applying this unique integrated technique revealed the lower per capita rates of the green zones in Al-Dammam metropolitan area by 3.52 m 2 /person than the defined standard of 5.9 m 2 /person of the Ministry of Municipal and Rural affairs of KSA. At the cities scale; in Al Dammam city, the per capita rate was 3.15 m 2 /person. While, in Al Khobar city the rate was 4.21 m 2 /person, and in Al Dhahran city the rate was 3.03 m 2 /person. Therefore, the per capita rates of the green zones in Al Dammam and Al Dhahran cities was sharply lower than the planning rates, while, the rate in Al Khobar city was fairly compatible with the standard planning rates.
There are 90 districts representing 66.7% of the total districts in Al-Dammam metropolitan area containing green zones, while the other 45 districts that represent 33.3% contained no green zones. There is deficiency in the coverage of the services to all the districts within time of (5, 10, and 15) minutes. The services coverage range from 75% to 98% of the districts. The "specialized parks" and "children's gardens" services came in the lowest rank by covering only 75% of the total districts. While, the "sports clubs" service came in the first rank by covering 89% of the districts. Al-Dammam metropolitan area suffers deficiency in fulfilling the needs of its population of green zones services. The deficiency was determined in this study by nine services to be established including two "sports cities", two "sports clubs", two "streets and squares gardens", one "district garden", one "children's garden" and one "specialized park"). This study provides a spatial decision support system that enables the decision makers to better evaluate and plan the green zones services in a scientific, balanced, reasonable and clear manner for seeking the sustainable development.

Conflict of Interest
The authors declare that there is no conflict of interest with any financial, personal, or other relationships with other people or organizations related to the material discussed in the article.