Mock Web-GIS app of multi-hazards susceptibility decision tree

7.3 Mock Web-GIS app of multi-hazards susceptibility decision tree

  Basically, the app will consist of two main parts; (i) formatted questions of causal factors for susceptibility assessment and (ii) GIS analysis and visualization with maps. In the question part, each question will be visible on the mobile device screen with YES, NO and Info tab. Depending on the answer given by the users (either YES or NO), next question will be visible to users to answer and proceed till to the end. In most of the individual questions, there will be Info tab to get further information regarding that question from GIS data stored in the app. On the other hand, in GIS analysis part, simple GIS functions such as overlay or spatial query, will be used based on the pre-loaded input layers. The user can accept the suggestions that are given based on the GIS operations, but can also decide to give a different answer. This can be due to the fact that the GIS data may be of insufficient quality, or could be outdated. For example, when using 30 m DEM data, slope values calculated might deviated considerably from those observed in the field, and the user can decide to allocate a different slope class than indicated by the system. This also applies for the outlines of the terrain units, which are made through automatic procedures outlines in section

  4.2.2, and are based on coarse resolution DEM data. This might require adjustment of boundaries of terrain units in the field. The app must have the opportunity to make such editing of boundaries, without generating entirely new terrain units, which would change the database structure considerably.

  It is proposed that he app interface has three windows on the mobile device screen (i) Question response window (ii) a popup window (where additional information will be visible by Info tab ) (iii) Map visualization window (Figure 7.3). At the beginning, the users need to provide some basic information about the identity of the user as well as select the terrain unit.

  Figure 7.3: Proposed architecture of the decision tree approach app of multi-hazards susceptibility assessment (MHSA) In the map window, some basic functionalities will be included such as zoom inout, pan, select features

  tool, north direction, scale, unit, map content layers with the ability of legend customization etc. In the map window, users are able to zoom their location to see the automated terrain boundary unit. By clicking on a

  terrain unit, user can identify hisher location based on GPS feature of mobile devices. The user doesn’t have to be located in the unit that is evaluated, because it also possible to evaluate units that are located on the other side of a steep valley. After that, users will start the multi-hazards susceptibility assessment for that unit by answering different questions which will be visible on the left of the screen one after another. There is also an Info tab by which users are able to see more information from the attribute table of different layers as well as from popup window (Figure 7.4).

  Figure 7.4: Sample question window with the attribute information by using Info tab in the proposed app

  As the terrain units have generated by considering automated approach, depending the field situation, it might require to edit it’s boundary. In case of editing the terrain unit boundaries, the app will have the As the terrain units have generated by considering automated approach, depending the field situation, it might require to edit it’s boundary. In case of editing the terrain unit boundaries, the app will have the

  Figure 7.5: Automated terrain editing option depending on field situation in proposed app

  The app needs to be developed in such a way that multi-hazards susceptibility can be assessed for the same unit by keeping a link between different hazards as presented in the decision tree. After completing all the steps of the assessment, the susceptibility assessment results will be viewable on the map. Also, the map window will show all the terrain units where the assessment unit will be displayed with separated colour (Figure 7.6). Besides, the attribute table of automated terrain unit layer will be modified by adding different fields such as assessment hazard types and susceptibility class as well as the basic information as provided at the initial stage of using app. It is also required to export those tables with different formats (e.g. csv, Excel) as well as preferred customized map. Finally, when the client (i.e. mobile devices) will be connected with the central server, the data will be synchronized, and with the objective to provide data that can covering bigger parts of a district and country. As the mobile Web-GIS app can also be used offline, this makes is use very effect especially in remote areas.

  Figure 7.6: Final results of multi-hazards susceptibility assessment of a terrain unit