34 results about "Risk zoning" patented technology

In various embodiments, points from flood maps (e.g., geospatial flood risk zoning maps) may be used in generating a flood frequency versus flood elevation curve for reducing the uncertainty in the flood risk assessment. In some embodiments, geospatial flood elevation lines for flood elevation lines at different flood frequency levels may be defined based on elevation datasets where there are inconsistencies between the elevation datasets and flood maps that were generated. The flood frequency versus flood loss curve may be derived based on the computed flood frequency versus flood elevation curve, digital elevation datasets, and collected damage curve. In some embodiments, the flood risk rating may also be derived and a flood risk assessment report may be generated.

The invention relates to a mountain torrent disaster risk division and prediction method based on GIS (geographic information system)-neural network integration. The method includes the steps: S1 mining the association relationship between a risk factor and a risk grade in a mountain torrent disaster by the aid of association rules, identifying the risk factor and building a quantitative mountaintorrent disaster risk evaluation index system; S2 determining risk and vulnerability index system by an analytic hierarchy process and the weight of the system to generate feature layers; S3 stackingmountain torrent disaster risk and vulnerability distribution layers by ArcGIS to obtain a mountain torrent disaster risk distribution diagram; S4 performing clustering by an ISO maximum likelihood method, merging regions from bottom to top and performing qualitative analysis from top to bottom to form mountain torrent disaster risk division; S5 analyzing non-linear relationships among evaluationindexes, the risk grade and disaster data by an Elman neural network, and building a mountain torrent disaster risk evaluation and loss prediction model. The problem of spatial scale uncertainty in mountain torrent disaster evaluation in a changing environment can be solved, and the method can be widely used for evaluating mountain torrent disaster risks.

The invention discloses a regional flood disaster risk evaluation and estimation method coupling a GIS algorithm and a GBDT algorithm. The method comprises the following steps: constructing a regionalflood disaster risk evaluation index system based on four types of disaster-causing factors, disaster-pregnant environments, disaster-bearing bodies and disaster prevention and reduction capacities,and normalizing the regional flood disaster risk evaluation index system to generate evaluation index layers; obtaining the optimal combination weight of each evaluation index, and generating four types of regional flood disaster risk distribution map layers; determining a final historical region flood disaster risk division map based on expert opinions; and constructing a regional flood disasterrisk evaluation model, predicting a future regional flood disaster risk, and generating a future regional flood disaster risk division map by using ArcGIS. The method has superiority for multivariatebig data processing, is suitable for basin or regional flood risk assessment and prediction, and can remarkably improve the calculation precision and the reliability of assessment and decision making.

In various embodiments, points from flood maps (e.g., geospatial flood risk zoning maps) may be used in generating a flood frequency versus flood elevation curve for reducing the uncertainty in the flood risk assessment. In some embodiments, geospatial flood elevation lines for flood elevation lines at different flood frequency levels may be defined based on elevation datasets where there are inconsistencies between the elevation datasets and flood maps that were generated. The flood frequency versus flood loss curve may be derived based on the computed flood frequency versus flood elevation curve, digital elevation datasets, and collected damage curve. In some embodiments, the flood risk rating may also be derived and a flood risk assessment report may be generated.

The invention relates to a 'three-map method' for evaluating ground fissures, comprising the following steps of: firstly, evaluating and zoning ground fissure risk to form a ground fissure risk zoning map, then evaluating and zoning ground fissure vulnerability to form a ground fissure vulnerability zoning map and finally evaluating and zoning ground fissure hazardness to form a ground fissure hazardness zoning map. The three-map method overcomes the defects that the prior art can not sufficiently reflect the natural and social attributes of disasters and can not comprehensively quantitatively evaluate ground fissure disasters, defines the concept of the geological disaster hazardness for the first time and puts forwards the viewpoint of evaluating the geological disaster hazardness for the first time. The invention provides an indoor similar material physical simulation analog test method for the cause of formation of the ground fissures, researches the structure characteristics and the fractional characteristics of the ground fissures and structure, physiognomy and earthquakes with the nonlinear idea for the first time and applies an artificial neural network (ANN) and geographic information system (GIS) coupling technique to evaluating the ground fissure risk.

The invention provides a lightning monitoring early-warning and alert service system comprising a lightning disaster risk zoning and thunderstorm disaster risk assessment system, a lightning alert service cloud platform, an urban-observation-based lightning monitoring and analysis internet cloud platform and a thunderstorm database. Therefore, an operational effect of lightning monitoring, forecasting, and protection technical services can be promoted; monitoring and warning ability of lightning disaster, the anti-thunder administrative capacity, and anti-thunder technical service levels can be enhanced; and the lightning protection and disaster reduction requirement by public security can be met. Meanwhile, one the basis of analyses of a plurality of cases during the thunderstorm process, rapid feature value extraction processing of the thunderstorm process and thunderstorm classification and determination can be realized; a reference basis is provided for lightning disaster zoning and analysis based on the thunderstorm characteristics; and the thunderstorm-characteristic-based lightning protection key points and protection strategic method are established, so that the system can provide basic analysis data for lightning early-warning and follow-up service and thus servers as a core support system for a lightning service.

The invention relates to a GIS-based typhoon disaster risk assessment method for a power grid. Through analysis and assessment of risk of typhoon, topographical sensitivity, fragility of the power grid and disaster prevention and mitigation capabilities, the typhoon disaster risk assessment method for the power grid is created. On one hand, compiling of a typhoon disaster risk zoning map for the power grid can be realized, and on the other hand, systematization and integrity of disaster risk division can be perfected to provide technical support for making a countermeasure for regional disaster prevention and mitigation.

The invention discloses a typhoon storm surge risk assessment method and a system based on an ArcGIS platform. The method has the advantages that compared with a traditional storm surge risk zoning strategy, the risk quantitative evaluation strategy is provided, and quantitative calculation is conducted on each factor (H, E, V and R) influencing the final risk value of the area to be evaluated. Therefore, the final risk value can be measured from two perspectives, one is a traditional risk level form, the other is an innovative quantitative mode, and a specific risk value can be obtained. Andthe method has important significance for disaster prevention, disaster reduction and disaster relief deployment. Meanwhile, only three parameters are considered at most in traditional risk division,an algorithm is provided for detailed calculation of each parameter, meanwhile, the disaster prevention and reduction capacity is considered, and therefore the completeness and reliability of an evaluation result are further improved.

The invention discloses a regional environment risk evaluation and division method based on a risk field. The method comprises: firstly, a regional environment risk evaluation index system framework is established based on a DPSIR model, the DPSIR model serves as a framework, regional ecological environment safety is guaranteed, an environment function area is effectively guided to serve as a target, and connotation of indexes is determined with analysis of an environment risk forming mechanism serving as a benchmark; then, evaluation index screening is carried out, and standardization processing is carried out on indexes; secondly, regional environment risk comprehensive level grading is carried out, the regional ecological environment safety comprehensive index is adopted for representing the regional ecological risk overall condition, finally regional environment risk zoning is carried out, and a risk acceptable area, a risk early warning area and a risk reduction area are determined. According to the invention, a regional environment grading and partitioning method system based on receptor vulnerability assessment and risk source hazard assessment is established, so that threats to ecological environment safety caused by prominent layout environment risks and high environmental pollution accidents at present are reduced.

The invention discloses a refined diagnosis method for urban agglomeration area flood risk zoning. The method comprises the following steps of using a GIS spatial data analysis function to carry out data rasterization and standardization processing on each index; constructing a judgment matrix corresponding to the index system; calculating the relative weight of each index and the flood risk degree of different grid units so that establishment of an urban agglomeration area flood risk degree evaluation model based on a fuzzy analytic hierarchy process and drawing of a flood risk map are realized. From the perspectives of rainstorm distribution characteristics, historical flood distribution characteristics, rainstorm ponding risk distribution characteristics of all cities and the like, theflood risk distribution characteristics of urban agglomeration areas are systematically diagnosed in an omnibearing and multi-angle mode. The flood risk degrees and risk levels of different dangerousareas are accurately calculated, a multi-index problem is scientifically and objectively synthesized into a single-index form, a single index capable of effectively measuring the flood risk degree isconstructed, and a reliable technical support means is provided for flood dangerous area division.

The invention discloses an ArcGIS-based all-region environment risk evaluation method. The method comprises the steps of collecting data; identifying an environmental risk source; characterizing the risk of an environmental risk source; Characterizing the environmental risk sensitivity index; Environment danger index representation; Environmental risk evaluation; Environment risk zoning. Accordingto the method, ArcGIS software is used for representing the environmental risk and the environmental risk sensitivity, the environmental risk of each position is determined, and on the basis, the regional environmental risk is more finely evaluated and analyzed.

The invention discloses an urban flood disaster risk assessment method fused with elasticity. The method comprises the following steps: dividing grid units based on the actual situation of a research area; obtaining the submerging water depth of each time period of each grid unit corresponding to the rainfall time sequence and the submerging water depth data duration of the rainfall of the session; taking the obtained grid units as calculation units, determining the maximum and minimum water depth threshold values of each land utilization type, and obtaining the elasticity of each grid unit in each time period by using the two threshold values, so as to obtain the average elasticity of each grid unit in each time period; selecting a plurality of risk indexes including elasticity and a plurality of vulnerability indexes; calculating and determining the weight of each index, and constructing an urban flood disaster risk assessment framework fused with elasticity; carrying out risk division on each index; carrying out risk zoning on the risk and vulnerability of the research area; and carrying out urban flood disaster comprehensive risk zoning on the research area. According to the method, the elasticity is integrated into an index system for urban flood disaster risk assessment as one of danger indexes, and the submerging depth change of almost the whole submerging process in single-session rainfall can be identified, so that the dangerousness under different submerging conditions in the risk assessment process is more accurately quantified.

The invention discloses a debris flow real-time dynamic risk evaluation method, which comprises the following steps of S1, inputting rainfall data and rock-soil body parameters into a TRIGRS model, calculating a stability coefficient Fs of a slope under different rainfall durations, judging that Fs is less than 1 as a source region, and judging that Fs is greater than or equal to 1 as a non-sourceregion; S2, inputting Fs and other evaluation factor layers such as confluence cumulant, gradient, plane curvature and lithology into the Flow-R model at the same time, identifying distribution of potential material source regions of the debris flow slope surface under different rainfall durations, and realizing coupling of the TRIGRS and the Flow-R model; meanwhile, based on field field investigation and remote sensing interpretation, distribution of existing loose matter source areas in the debris flow channel is recognized; and S3, based on a Flow-R model, calculating debris flow energy and risk probability distribution under different rainfall durations, and performing debris flow real-time dynamic risk zoning; according to the method, the problems that debris flow source distributionis not comprehensively considered and static evaluation and research of debris flow risk are emphasized in multiple aspects in the prior art are solved.

The invention provides a regional water environment risk zoning method comprising the steps that a driving force factor, a pressure factor, a state factor, an impact factor and a response factor of a DPSIR module are determined; a regional water environment risk assessment index system is constructed, and the constructed regional water environment risk assessment index system comprises a target layer, a system layer, a criterion layer and an index layer which reflect the regional water environment risk from different angles; the weight of each index is calculated by using the analytic hierarchy process and value assignment is performed, and then all the index systems are quantitatively graded; then the regional water environment risk value is calculated through a fuzzy comprehensive evaluation method; and the regions are divided into a high-risk region, a medium-risk region, a low-risk region and a no-risk region in a decreasing order according to the risk with ArcGIS acting as an auxiliary tool. According to the scheme, the regional water environment can be more accurately assessed so as to provide accurate basis for decision.

The invention discloses a three-layer risk assessment drought disaster risk coping method. The method includes the following steps that: regulatable feature and regulation approach analysis is performed on drought disaster risk factors from the four aspects of dangerousness, exposure degree, vulnerability and disaster prevention and mitigation capability involved in a drought formation process; a drought disaster one-layer risk assessment system is established; a drought disaster two-layer risk assessment system is established; a drought disaster three-layer risk assessment system is established; and drought risk coping strategies are put forward. Based on historical evolution rules and future evolution trends of drought disasters, the drought disaster risk coping method is established according to drought disaster risk region division and risk prediction results from aspects such as urban population size, regional water resource carrying capacity, industrial structure adjustment, water conservancy project group optimized layout, disaster prevention and mitigation capacity construction, soil and water resource regulation and risk prevention and control management. With the method adopted, regional drought risks can be lowered level by level.

The invention relates to a method for sudden accident risk zoning of a river basin based on changes of water resources, which comprises the following steps: 1) carrying out drought risk zoning within a selected zone scope according to drought risk indexes; 2) carrying out flood disaster zoning within the selected zone scope according to flood risk indexes; 3) carrying out sudden accident risk zoning within the selected zone scope according to sudden accident risk indexes; and 4) superimposing zoning results in a GIS (geographic information system) to realize sudden risk zoning under different precipitation conditions. The conditions of the water resources are taken to account for sudden accident risk zoning, the sudden accident risk zoning results of zones are more reasonable and reliable, and the scientific level of regional environmental management can be improved. Moreover, the sudden accident risk zoning results of the zones can be displayed promptly through the GIS technology, and the accuracy of integrated environmental management can be improved. Meanwhile, the method has high operability and a wide scope of application and is suitable for zones of different sizes.

The invention discloses a long-river-reach multi-breach ice flood flood inundation combined risk assessment method. The method sequentially comprises the steps of basic data collection and processing, long-river-reach multi-breach ice flood flood inundation combined risk assessment index system construction, breach danger section selection and ice flood season dike danger degree assignment, ice flood dike burst flood inundation process simulation calculation, long-river-reach multi-breach ice flood flood inundation combined risk degree calculation and long-river-reach multi-breach ice flood flood inundation combined risk zoning and assessment, wherein the ice flood flood inundation combined risk degree calculation comprises combined risk assessment index assignment, combined risk assessment index weight calculation and ice flood flood inundation combined risk degree calculation; and the long-river-reach multi-breach ice flood flood inundation combined risk zoning and assessment comprises ice flood flood inundation combined risk degree hierarchical clustering, combined risk degree risk zoning and combined risk assessment. The long-river-reach multi-breach ice flood flood inundation combined risk assessment method provided by the invention has the advantages of being rigorous in design, practical and suitable for application.

The invention discloses a rainstorm high-risk zoning method based on hydrometeorological region linear moment frequency analysis, and relates to the technical field of flood prevention and disaster reduction hydrometeorology. The specific scheme is that the method comprises the following steps: S1, carrying out data collection, screening and quality control; S2, analyzing the applicability and superiority of a regional linear moment method; S3, conducting hydrometeorological consistent area division; S4, carrying out linear selection of optimal distribution of a consistent area; S5, carrying out frequency estimation value calculation and space-time consistency adjustment; S6, drawing a rainstorm high-risk division map. The rainstorm high-risk zoning method based on hydrometeorological region linear moment frequency analysis provided by the invention not only can obtain a rainfall frequency estimation value with relatively high precision and accuracy, but also can reflect a spatial distribution relationship among the occurrence probability of a strong rainfall intensity-rainstorm falling area-probability of occurrence so as to analyze the rainstorm high-risk zoning, and can providea scientific basis for engineering flood control design, flood control planning design of regions and cities and early warning of mountain torrent disasters in a short duration.

The invention provides a soil heavy metal pollution risk area division method and device, electronic equipment and a medium, and the method comprises the steps: constructing a soil heavy metal pollution risk grade prediction model based on a random forest algorithm through employing a soil heavy metal pollution risk area division sampling point data set, optimal factors are screened according to correlation among important factors and factor importance, an optimal input variable set is generated, the optimal input variable set and an optimal parameter set generated by an optimization prediction model are input into the prediction model together, an optimized prediction model is generated, the risk level of a rule interval point set of a to-be-divided risk area is calculated through the optimized prediction model, and the risk level of the to-be-divided risk area is calculated. And finally, carrying out optimization processing to generate the soil heavy metal pollution multi-level risk areas of the to-be-divided areas according to the risk level data. By applying the method, the device, the electronic equipment and the medium in the embodiment of the invention, the accuracy of the risk zoning boundary is effectively improved, and the problem of strong dependency of a geostatistical spatial interpolation method on the representativeness and the number of sampling points is solved.

The invention relates to a township-level tsunami risk assessment method based on Thiessen polygons. The method comprises the following steps: constructing a plurality of Thiessen polygon structures in a coastal area based on basic geographic information data of the coastal area; according to historical earthquake and tsunami data in the coastal area, obtaining a tsunami danger level analysis result of each Thiessen polygon structure in combination with a tsunami numerical calculation model; obtaining a vulnerability evaluation result based on the ASTER elevation, the Sentinel1 data, the LANDSAT satellite data and the NPP / VIIRS light data; and combining the tsunami danger level analysis result and the vulnerability assessment result of each Thiessen polygon structure to obtain a township-level tsunami risk zoning result for display. According to the method, the tsunami risk assessment zoning scale is improved to the township level, tsunami fragility analysis is scientific and practical, and the fragility analysis reasonability is improved.

The invention provides a grape late frost meteorological disaster assessment method and system, and the method comprises the steps: carrying out the comprehensive collection and analysis of a variety of information, obtaining a disaster risk assessment model, inputting the collected real-time early warning information, short-term early warning information and short-term forecast into the disaster risk assessment model, and obtaining a disaster risk assessment result; and according to the occurrence time of the grape late frost, carrying out disaster influence analysis, carrying out operation on an analysis result and a disaster-bearing body to obtain a disaster risk zoning result, and pushing the result to related industrial personnel in time, so that the efficient and automatic estimation and evaluation of the grape late frost meteorological disaster are realized.

The invention discloses a power grid system geological disaster risk assessment method and system based on heavy rainfall. The assessment method comprises the following steps: dividing a region to be measured into a plurality of 3km * 3km grid regions; selecting factors with relatively high correlation with geological disaster occurrence, wherein the factors comprise a rainfall factor and a geological factor; carrying out statistics on the distribution probability of historical geological disasters in each factor; performing interval division on each factor, and determining a distribution probability and a risk level of a historically occurring geological disaster in each factor interval by using an information amount method; building a matter element evaluation grade by utilizing an extension matter element model; performing overall assessment on the geological disaster risk level of the to-be-measured area. According to the invention, geological disasters having significant influence on the power grid system can be analyzed, disaster-inducing factors such as heavy rainfall and geographic information are integrated, the extension matter-element model is adopted for modeling for risk evaluation research, and risk zoning grade evaluation of the geological disasters of the target power grid system is obtained.

The invention discloses an elastic evaluation method considering the influence duration of system performance and the water flow velocity. The method comprises the following steps: constructing an urban flood one-dimensional and two-dimensional coupling model and dividing grid units; simulating to obtain surface submerging water depth and water flow velocity of each grid unit in each time period corresponding to the rainfall sequence; dividing the land utilization type of each grid unit; determining the system performance of the grid unit of which the land utilization type belongs to the non-traffic land in each time period; determining the system performance of the grid unit of which the land utilization type belongs to the traffic land in each time period; determining the influence duration of the system performance of each grid unit; and improving a grid-based elasticity evaluation method, and determining the time period average elasticity of each grid unit. According to the method, the flood disaster resistance, adaptation and recovery capabilities of an urban system are reflected, so that the urban flood disaster risk zoning is better realized.

The invention discloses a regional flood disaster risk assessment and prediction method coupled with GIS and GBDT algorithm, which includes the following steps: constructing four types of regional floods based on disaster-causing factors, disaster-forming environment, disaster-affected body, and disaster prevention and mitigation capabilities Disaster risk evaluation index system, and normalize it to generate each evaluation index layer; get the optimal combination weight of each evaluation index, generate four types of regional flood disaster risk distribution layers; determine the final layer based on expert opinion Historical regional flood disaster risk zoning map; build a regional flood disaster risk assessment model to predict future regional flood disaster risk, and use ArcGIS to generate future regional flood disaster risk zoning map. The method of the invention has advantages in processing multi-variable big data, is applicable to river basin or regional flood risk assessment and prediction, and can significantly improve calculation accuracy and reliability of evaluation and decision-making.

The invention discloses a rainfall frequency atlas digitization and rainstorm high-risk zoning visual analysis system, relates to the technical field of hydrometeorology of disaster prevention and reduction, and aims to check and analyze frequency estimation values of any point (including an observation rainfall site and a data-free site) in a research area in different design periods and different frequencies (recurrence periods)n check and analyze rainstorm high-risk regionalization maps of different time periods and different frequencies (recurrence periods) according to different interpolation methods, and perform rainstorm magnitude analysis, and rainstorm disaster meteorological risk early warning and the like through real-time rainfall data updating. The system can be used for guiding work in the fields of regional flood control planning, urban inland inundation prevention and control planning, engineering construction planning and design, flood disaster prevention and early warning and the like. According to the specific scheme, the system comprises a rainfall frequency estimation value and rainstorm high-risk regionalization diagram analysis unit, a rainstorm analysis unitand a real-time analysis unit.

The invention discloses a dynamic risk assessment method for mountain torrent disasters coupled with hyperspectral monitoring and GIS. It includes the following steps: Step 1: Construct a hyperspectral remote sensing technology application system; Step 2: Extract information related to mountain torrent disasters; Step 3: Simulate the evolution and disaster process of single and compound disasters; Step 4: Build a stepwise regression equation ; Step 5: Determine the index system of the risk of mountain torrent disaster; Step 6: Obtain the risk map of mountain torrent disaster and the result map of mountain torrent disaster vulnerability; Step 7: After normalization, obtain the risk map of mountain torrent disaster at multiple spatial scales; Step 8 : To divide the flash flood disaster risk zoning in a specific area. The invention has the advantages of realizing the accuracy, reliability and timeliness of the basic data in areas prone to mountain torrent disasters.

The invention relates to a mountain torrent disaster risk division and prediction method based on GIS (geographic information system)-neural network integration. The method includes the steps: S1 mining the association relationship between a risk factor and a risk grade in a mountain torrent disaster by the aid of association rules, identifying the risk factor and building a quantitative mountaintorrent disaster risk evaluation index system; S2 determining risk and vulnerability index system by an analytic hierarchy process and the weight of the system to generate feature layers; S3 stackingmountain torrent disaster risk and vulnerability distribution layers by ArcGIS to obtain a mountain torrent disaster risk distribution diagram; S4 performing clustering by an ISO maximum likelihood method, merging regions from bottom to top and performing qualitative analysis from top to bottom to form mountain torrent disaster risk division; S5 analyzing non-linear relationships among evaluationindexes, the risk grade and disaster data by an Elman neural network, and building a mountain torrent disaster risk evaluation and loss prediction model. The problem of spatial scale uncertainty in mountain torrent disaster evaluation in a changing environment can be solved, and the method can be widely used for evaluating mountain torrent disaster risks.

The invention provides a chemical industrial park gridding environment risk assessment and partitioning method based on a risk field. According to the method, a chemical industrial park risk zoning index system is constructed from four aspects of an environmental risk source risk index, atmospheric environmental risk field intensity, water environmental risk field intensity and environmental riskreceptor vulnerability; gridding refined environmental risk assessment of the chemical industrial park is realized based on the risk field. The environmental risk source risk index, the risk field intensity and the environmental risk receptor vulnerability of each grid unit in the chemical industry park can be obtained, and a basis can be provided for identification and screening of high-risk areas and high-risk links of the chemical industry park, implementation of risk zoning management and optimization and adjustment of park space layout.

The invention provides a lightning monitoring early-warning and alert service system comprising a lightning disaster risk zoning and thunderstorm disaster risk assessment system, a lightning alert service cloud platform, an urban-observation-based lightning monitoring and analysis internet cloud platform and a thunderstorm database. Therefore, an operational effect of lightning monitoring, forecasting, and protection technical services can be promoted; monitoring and warning ability of lightning disaster, the anti-thunder administrative capacity, and anti-thunder technical service levels can be enhanced; and the lightning protection and disaster reduction requirement by public security can be met. Meanwhile, one the basis of analyses of a plurality of cases during the thunderstorm process, rapid feature value extraction processing of the thunderstorm process and thunderstorm classification and determination can be realized; a reference basis is provided for lightning disaster zoning and analysis based on the thunderstorm characteristics; and the thunderstorm-characteristic-based lightning protection key points and protection strategic method are established, so that the system can provide basic analysis data for lightning early-warning and follow-up service and thus servers as a core support system for a lightning service.

The invention discloses a method for landslide disaster risk zoning in small watershed areas based on mechanism analysis, comprising the following steps: step 1, establishing slope units for landslide disaster risk zoning in small watershed areas; step 2, calculating risk evaluation indicators for each slope unit , and carry out normalization process to described risk evaluation index, set up the geographical information database of slope unit; Step 3, calculate the value of the comprehensive risk degree Z of each slope unit, obtain the integrated risk zoning result of landslide disaster in this small watershed area. On the one hand, the index system and the spatial unit of the present invention start from the formation mechanism of disasters, and the zoning results are more objective and scientific; on the other hand, it provides suitable spatial precision for disaster prevention, making the risk zoning results more instructive.