Geospatial modeling of the location of bomb shelters in residential areas of the city

The purpose of the article is to determine the optimal placement of the bomb shelter in the existing urban development. To achieve this goal, the authors used geoinformation systems. The authors set the task of processing topographic and geodetic data and related information. The authors implemented the task employing spatial analysis using existing ArcGis software modules. The use of the geoinformation system in the article makes it possible to significantly increase the speed of information processing than when using traditional methods. The use of the geoinformation system by the authors allows the creation of geodatabases with all the necessary attribute information. The authors researched the example of 522 micro-districts of the Saltivsky residential area of Kharkiv. The intellectual analysis of the existing information was carried out in this work using the geostatistical method for data transformation from a discrete to a continuous representation. In the article, the authors solved the task of determining the location of civil protection facilities using many factors and requirements. Visualization of the dangerous zones of the explosion of building debris during destruction, determination of the optimal route of movement of the population to the bomb shelter, and determination of the time required for this carried out. The obtained results, presented in the form of an algorithm, will make it possible to use the proposed sequence of actions to solve similar problems in the future. The authors developed an algorithm that significantly reduces the time for processing topographic and geodetic data and related information and solves the task of determining the location of civil protection facilities using many factors and requirements.


Problem statement
Determining the optimal location of a bomb shelter (object of civil protection of the population) in already formed residential areas is a time-consuming and long-term task.Such research relates to the formation of bomb shelters on a plot of land to protect the civilian population from the shrapnel effect of shells, debris from destroyed buildings, poisonous gases, and radiation.
Over the past 30 years, no one has investigated the problem of determining the optimal location of a bomb shelter.Bomb shelters were actively built during the Second World War and several years after its end.In that period of history, specially built bomb shelters were created and the basements of buildings in large cities were adapted for the protection of the population, and the use of underground subway facilities was planned.
After the collapse of the USSR, bomb shelters were no longer built, on the contrary, bomb shelters were only rebuilt or destroyed.Ukraine got the Soviet infrastructure with the lack of protective structures for the civilian population.Thus, the study of the issue of proper storage and operation of bomb shelters in Ukraine was not conducted.The study of this topic is very relevant for all Ukrainian cities, as well as, for Kharkiv.Currently, during military operations, the issue of designing and building bomb shelters is relevant due to many rocket and artillery attacks on the civilian population.The research carried out by the authors showed that it is possible to design, build or place a room under a bomb shelter: • in basements; • in premises where it was previously planned to place parking spaces; • at subway stations; • in rooms on the first floor, protected from the outside by load-bearing walls and with the absence of window and door openings; • in a new location determined with the help of GIS.
Today, most civil protection facilities are abandoned, in poor condition, or destroyed.In this regard, precisely during active hostilities, a problem arose related to the lack of reliable bomb shelters.In the article, the researchers consider the problem of designing bomb shelters in a new location determined with the help of GIS.

Literature review
The design of the optimal location of bomb shelters in residential areas with subsequent operation is subject to clause 16 of part 17 of the Civil Defense Code and clauses 11, 18, 19 [1].This task is quite complex and requires the analysis of many factors and requirements.The procedure for the creation and maintenance of protective structures of civil defense and their record keeping was approved by the Resolution of the Cabinet of Ministers of Ukraine No. 138 [2].
For example, today, in one of the underground parking lots of the Kharkiv office center, converted into a bomb shelter, residents are hiding from dangerous shelling by Russian soldiers.The rooms of the bomb shelter have heating, ventilation, a storage tank with water, a certain supply of food, and even showers -everything necessary [3].In the future, the design of new buildings with reinforced underground parking lots, which can be used as a reliable bomb shelter, is being considered.The mayor's office of Kharkiv, which suffered the most during the hostilities, prepared recommendations for developers on the arrangement of "safe rooms" using Israeli experience.A protective room with reinforced walls with a minimum area of 9 m 2 provided within the apartments.A new building should have a separate riser of such rooms, but the arrangement of these safe rooms will significantly increase the cost of the apartment.However, constant rocket and artillery attacks on the cities of Ukraine have shown that for the safety of the civilian population today, it is necessary to build new bomb shelters in populated areas.
Thus, today the government of Ukraine plans to introduce changes to building regulations.There is a need to consider Israel's experience in the planned reconstruction of housing, infrastructure, and bomb shelters.The issue of security is planned to be regulated at the legislative level with prescribed norms and rules [4].
Bomb shelters made of reinforced concrete are of great importance for the protection of people during hostilities.Functional requirements for such structures differ from ordinary residential or commercial structures.Therefore, other approaches are used for the design and construction of bomb shelters.For example, the explosion resistance of such structures should be maximum, especially in the conditions of hostilities, in such countries as Ukraine, Afghanistan, Israel, Syria, and Lebanon.There are developments in the use of ground explosion-proof sheltered cylindrical configurations consisting of vertical and inclined walls with a flat roof made of concrete and steel [5].
It is also necessary to add that the creation of bomb shelters or places to accommodate the population during natural disasters are costly project.The cost of the bomb shelter construction program depends on the population in the risk zone.Such a cost can be equal to the cost of a large military strategic system [6].
For houses that were built earlier, it is necessary to build separate bomb shelters where people can feel safe.The location of such civil protection facilities must be chosen carefully, based on many factors [7].The issue of finding a city for a future bomb shelter is quite difficult because it is necessary not only to find a free place for construction in an already built-up massif but also to consider psychological and physiological factors of human life [8].An important feature is that it is necessary to consider the fact that much of the young population either evacuated or is serving in the army, that is, most elderly people remained in the cities.
That is why great importance should be attached to the optimization of evacuation routes for vulnerable population groups when searching for a place to locate a bomb shelter.Also, it is important to develop a road map showing the routes to bomb shelters [9].
Emergency shelters, which provide places for temporary accommodation of the population during natural disasters, play a dual role, they can also be used as bomb shelters.Great attention should be paid to the optimization of location selection.It is necessary to pay attention to the experience of other countries.Special attention should be paid to the optimization of site selection issues using spatiotemporal regularities.Such storage facilities should be designed considering different types of natural disasters [10].

Materials and method
Currently, in the city of Kharkiv (Ukraine), as in most modern large cities, there are "sleeping" districts.The peculiarity of these compact places of residence of the population is that almost all the buildings are multi-story and quite close to each other.There are almost no undeveloped areas of the territory.Low-rise buildings (two-and three-story) -kindergartens, schools, and heat distribution stations are unevenly located in the district and in small numbers.To solve the goal set by the authors, namely, to determine the place of the optimal location of the bomb shelter in the already existing urban development, a typical micro district of the Saltivka residential area number 522 was chosen as an example (figure 1).
The peculiarity of this residential massif is the very compact living of people and the fact that the construction was carried out on alluvial soils and sands.The compositions decision of the designers was based on the discovery of plastic groups of rhythmically repeating buildings located along the central pedestrian alley leading to the Zhuravlivsky Hydro-park.The cultural and household services of this consolidated neighborhood were decided according to the principle of "focusing" [11].Approximately 28,587 people live in the micro-district.
Choosing the location of a bomb shelter in such a densely populated neighborhood requires the processing of large volumes of diverse information and using information technologies designed for modeling spatial data.Modern means of analysis and visualization of territorial placement and modeling based on the use of geoinformation technologies [12,13].
The main reason for the inclusion of geographic information systems (GIS) in solving the task of designing the placement of a bomb shelter is spatial analysis and decision support based on mathematical and cartographic modeling, visualization, forecasting, and evaluation.The use of GIS allows you to create a detailed visualization and conduct a qualitative spatial analysis [14,15] of the location of the bomb shelter concerning the territory.The simulation, the results of which are presented in this work, was done using the capabilities of the software product from the American company Esri -ArcGIS.
A personal geodatabase with the necessary layers was created to display the built-up objects of the micro-district.As a result of studying the necessary objects for further analysis, it was decided to use the following layers in the geodatabase: • Layer Building1 (polygonal) -for displaying buildings.
• Layer Polygon1 (polygonal) -for displaying the boundaries of the neighborhood.
• Layer Streets ND (dotted) -for displaying walking routes to the bomb shelter.
• Layer Streets2 (linear) -for displaying footpaths.For all layers, the USC 2000 zone 7 coordinate system was set.The initial data for vectorization were the materials of the general plan of the Kharkiv.As a result, a digital model of the territory of micro-district 522 of the Saltivsky residential massif was created, considering residential and non-residential buildings (figure 2).
After vectorization, the data was entered into the attribute tables of the corresponding layers.These data will be needed in the future for calculations and analysis of the land plot.An example of a filled attribute table for a point layer of sewer hatches (Luki1) is shown in figure 3.
One of the important characteristics of the 522 micro district is the presence of two metro stations (Heroiv Pratsi and Studentska).During air raids and shelling, they can perform a protective function for people living nearby.There are also three three-story school buildings in the neighborhood.The peculiarity is that all three schools are located next to each other, and thanks to the presence of stadiums with football fields in two of them, all these schools are at a considerable distance from the adjacent residential development.
To mark on the digital map dangerous zones (on which debris does not fall in the event of a building collapse), it is necessary to calculate the distance of debris falling around the buildings.For this, we will use the following formula: where E is the number of floors; 2.9 is the floor height; 1.5 is the height of the semi-basement; 2 is the height of the technical floor.
To determine the height of the only 25-story building in the neighborhood, you need to add 7.2 m, since the technical floor and semi-basement are much higher, unlike the buildings of the old version, which built the entire neighborhood.On the given fragment of the digital map (figure 4) the zones of debris spread around all the houses in the neighborhood are marked.From figure 4, from the south, schools are at a safe distance from residential buildings, and if they collapse due to the impact of shells, a large free area remains.Therefore, the authors proposed the creation of bomb shelters on the territory of school sports fields.The location of the bomb shelters themselves are marked on the digital map with dots.Thanks to the calculations carried out in the work, it is proposed to create three warehouses with 2500 places in each.
None of the bomb shelters fall into the area of the explosion of building debris, so the entrance to them not be blocked for the public.Three bomb shelters can accommodate 7,500 people.Approximately 28,587 people live in the micro-district.It means that approximately 30 percent of the population will be to stay in a safe place.The rest of the population can find shelter in the two existing metro stations.
In our opinion, a large civil defense structure should not be built, since, in case of damage to the bomb shelter with high-precision heavy weapons, it will not be possible to move the population to another shelter.In the case of a blockage of the entrance door of the protective structure due to a direct hit, several emergencies exit for evacuation are provided in each structure.And thanks to the fact that the three storage facilities are located next to each other, the civilian population will be able to quickly move to another storage facility.It is more appropriate to build three small bomb shelters, and place sports school grounds and stadiums on top of them.Thus, children are not left without the opportunity to conduct physical education classes in the open air.
To reach the bomb shelter in the event of an alarm, the civilian population needs approximately 15 minutes according to safety standards.Therefore, it is necessary to perform the following calculations for each of the four corners of the neighborhood and determine the time and optimal walking route.The Network Analyst module of the ArcGIS geographic information system was used for this task.The results of the analysis shown in the figure 5. Routes of movement to the bomb shelter from different ends of the 522 micro district and they demonstrate optimal routes from the northeast corner (10 minutes), from the southwest corner (11 minutes), from the southeast corner (4 minutes), from the northwest corner (15 minutes) (figure 5).As you can see, no route exceeds the 15 minutes recommended by regulations.
The received optimal walking routes to bomb shelters must be sent in advance to all residents of the neighborhood using social networks and printed and distributed.
One of the most important stages of determining the optimal place for a bomb shelter in an already existing residential building (figure 6) is the development of a geodatabase, which includes all the necessary factors for choosing the location of a civil defense facility.

Results
1.The authors developed a digital geoinformation model of 522nd micro-district of the Saltivska residential area of the city of Kharkiv with the introduction of a significant amount of attribute data.2. The optimal routes to the designed bomb shelters were calculated using geographic information systems and displayed on digital maps.3.In the article, calculations are made regarding the distance of debris flying around buildings, and dangerous zones are displayed on a digital map.
4. Reference with the fact that the task of finding a place for the location of a civil protection facility in an already built residential area must be solved not only in Ukraine but also in many other countries of the world.An important feature of the work is that such a design was not foreseen at the stage of development of the master plan of the city's residential area.The authors have developed an algorithm for solving the task of finding a place for the location of a civil protection facility in an already built, crowded residential area. 5.In the research conducted by the authors, the locations of bomb shelters were determined based on the results of the analysis of many factors.

Conclusions
Thus, the geospatial modeling used by the authors made it possible to carry out actions to determine the optimal location of the protective structures of the civilian population.The calculations obtained by the authors enable the government and regional authorities to create a civil protection facility for the population in built-up areas.
The application of geoinformation technologies for modeling the optimal placement of bomb shelters in residential areas allowed for considering many factors, such as the spread of debris around buildings, and the optimal route of movement to the bomb shelter.That is, the authors proposed how to solve the task with minimal time expenditure and with the lowest probability of error.With the help of a spatial analysis performed in the ArcGIS geoinformation system, a place was chosen for the construction of a bomb shelter for the civilian population in the 522nd micro district of Kharkiv.A digital geoinformation model of 522 micro districts of the residential area of the city of Kharkiv has been developed.
In the work, with the help of the ArcGIS software package, a geodatabase of this neighborhood was developed, which made it possible to determine the number and location of civil protection facilities.In the future, it is possible to use the proposed sequence of actions to solve similar problems.
In general, the intelligent analysis of geostatic models can be used to process data in any locality thanks to the use of a geostatistical method to transform data from a discrete to a continuous representation.

Figure 1 .
Figure 1.View of the 522nd micro district left -map; on right -is a satellite.

Figure 2 .
Figure 2. Digital model of the 522nd micro district.

Figure 3 .
Figure 3.The fragment of the attributive table with data on sewer manholes.

Figure 4 .
Figure 4.A view of the scattered debris zones around the houses.

Figure 5 .
Figure 5. Routes of movement to the bomb shelter from different ends of the 522nd micro district.

Figure 6 .
Figure 6.Algorithm for finding the optimal place for the location of the civil protection facility.