Run Basic InaSAFE¶

a. Run InaSAFE Analysis¶

Click Run in the lower right corner of the InaSAFE panel to start the analysis process. If everything was set up correctly, you should get a result in the dock area after a few seconds, and a new map layer should be added to the map.

b. Interpret the results¶

The new impact layer will be generated and called Number of structures. Let’s take a look at the new impact layer generated by InaSAFE.

• Zoom in to some area on the map canvas

• Here we have zoomed in to a location showing two rivers going through the middle of Jakarta. There will be five new different colours generated from InaSAFE (red, orange, light yellow, green, and grey).

• The red buildings are situated in High Hazard with inundation water greater than 1,5 metre. The orange buildings are situated in a Medium Hazard with inundation water between 0,7 - 1,5 metre. The light-yellow buildings are situated in Low Hazard with inundation water between 0,1 - 0,7 metre. The green buildings show you that these buildings are currently not classified as an affected building, but, we can identify these buildings with Use Caution. It is like some kind of warning system, so we can identify which buildings needs more attention when the flood happen. The grey buildings considered as unaffected with the flood hazard model.

• Click Number of structures in the layer list to select it and click Identify Feature tool and then click on a building to view the attributes of that building.

In the InaSAFE panel we now see the impact summary. The details of are explained below.

• Analysis Question: describe what kind of analysis happens in this scenario

• General report: InaSAFE divides the result into several categories based on the threshold set in the hazard analysis. In this impact summary, InaSAFE divides the estimated number of structures based on two categories, Hazard Zone (buildings affected based on High, Medium, Low, and Use Caution class) and Structures (buildings affected based on Affected by flood, Not Affected by flood, and Not Exposed by flood)

• Analysis detail: describe more detail about estimated number of structures by structure type. In this impact summary, InaSAFE breaks down the results into a more detailed report by looking at each type of the structure, for example, the number of residential affected by flood is 4.300, meanwhile, the number of education structures affected by flood is 210. We can see more detail about the type of structuress affected by the hazard in this section.

• Action checklist: designed to make disaster managers think about what they need to do/discuss when planning for a similar event in the future.

• Notes & assumptions: provides details about the input data and any limitations or assumptions in the analysis or report summary. In this example, it explains why buildings are said to be inundated, wet and dry.

• Analysis detail: gives the information about data source, and details about analysis that we have

The results show the buildings that will be affected by flood water 1m deep. But what if the disaster manager decides that buildings in 80cm of water are also flooded? In order to assess this new scenario, we need to change the water depth threshold at which buildings are considered to be inundated. With InaSAFE it is easy to run a new scenario, all you need to do is change the Thresholds [m] in the InaSAFE Keyword Creation Wizard and run the scenario again. We will do this next.

c. Changing threshold¶

In the Jakarta flood scenario we are running; the threshold refers to the depth of water that a disaster manager decides is the boundary between buildings being flooded (affected) and buildings not being affected.

If you want to change the thresholds for the flood in this scenario, you can do it from InaSAFE toolbar menu and select Keyword Creation Wizard. But, before you select on Keyword Creation Wizard menu, make sure that you already selected the flood layer in the layer panel window.

If you want to open the InaSAFE question panel again, click on Show question form at the top of the InaSAFE panel. You will see the InaSAFE question panel again and you can click the Options button next to be flooded.

InaSAFE Keyword Creation Wizard will automatically show on your screen. We must define the flood as a Hazard layer, therefore, please select Hazard and then click Next.

Follow all the step and click Next until you found changing thresholds menu like this:

Choose Flood classes to define the thresholds. Look at the right bottom of your screen. You can see the configuration of the thresholds and now you can make change to the thresholds.

In this case, we define that the flood impact has 4 classes; High, Medium, Low, and Use Caution. In each class, we can define the minimum and maximum value for each thresholds. The threshold is automatically set that High classes is the area greater than 1.5 metre of inundation, Medium class is the area with 0.7 - 1.5 metre of inundation, Low class is the area with 0.1 - 0.7 metre of inundation, and last, Use Caution class 0 - 0.1 metre. We can define each threshold based on our needs. If we want to change the value, you can change it manually. The analysis result will be different if we see different value for each classes.

After finish changing the thresholds, don’t forget to click Save and finish all steps needed. Close the dialog window and then run the analysis again to see the change in the result.

When the function completes, take a look at the impact summary in the InaSAFE panel. How do the results compare to the first analysis results? The result should be different to the first analysis because we have changed the thresholds for each classes.

This completes our first InaSAFE analysis using the flood hazard model to look at the number of affected buildings.

a. Run InaSAFE Analysis¶

If everything is setup correctly, the InaSAFE dock should show that you are ready to run a flood analysis on population. It poses the question “In the event of a flood similar to the 2007 Jakarta event, how many people will be affected?” In this analysis we will use the default flood depth threshold by Flood classes. After everything is setup accordingly click Run to process the new scenario.

b. Interpret the results¶

If everything was set up correctly, you should get a result in the dock area after a few seconds, and a new map layer should be added to the map. The new impact layer will be called Number of people. Let’s explore the result again to make you understand more about the InaSAFE result.

1. Turn off Number of structures layer and drag the Number of people above a flood similar to 2007 Jakarta event

2. Zoom in to an the area you choose

3. Select Number of people in the layer list and use Identify Feature tool again to select a pixel (square) in the map canvas.

4. Here we clicked on one of the red pixels and find that there is a population exposure count with value of 78, which means there are approximately 78 people in this one pixel (square) who need to evacuate because of the flood.

In the InaSAFE panel we now see the impact summary. The details of this summary are explained below.

• Analysis question: describe what kind of analysis happens in this scenario

• General report: InaSAFE divides the results into several categories based on the thresholds set in the hazard analysis. in this impact summary, InaSAFE divides the estimated number of people based on two categories, Hazard Zone (Hgh, Medium, Low, and Use caution) classes based on the thresholds that we defined before and Population (population affected based on Affected, Not affected, and Not exposed by flood)

• Minimum needs: these are the calculated amounts of food, water, and other products that are needed by evacuated people. These needs should be provided weekly.

• Action checklist: designed to make disaster managers think about what they need to do/discuss when planning for a similar event in the future.

• Notes and assumptions: provides details about the input data and any limitations or assumptions in the analysis or report summary. In this example, it shows the total number of population in the analysis area and the source of minimum needs.

• Detailed demographic breakdown: this part of analysis give more information about the demographic of people affected by flood. We can see the breakdown based on age or gender.

• Analysis detail: gives the information about data source, and details about analysis that we have.

c. Understand defaults minimum needs¶

The InaSAFE impact summary for flood impact on people includes details for the amount of drinking water, rice, clean water, and family kits and for the number of toilets that should be provided for displaced persons each week. The minimum needs in the Jakarta flood impact assessment are based on the Head of Indonesia National Disaster Management Authority, BNPB, regulation, PERKA No 7/2008 guideline procedure for fulfillment of basic needs in Disaster Response. The default minimum needs formula is:

• 400g rice per person per day (2.8kg per week)

• 2.5l drinking water per person per day (17.5l per week)

• 15l clean water per person per day (105l per week)

• one family kit per family per week (assumes five people per family which is not specified in perka)

• 20 people per toilet

As described above, the impact summary and minimum needs calculation is based on the default world population demographics (which assumes a ratio of 26.3% youth, 65.9% adult and 7.9% elderly).

You may like to refer to local population statics (for example - Population of DKI Jakarta) to change these defaults for your analysis area, similarly if you have other regulation for minimum needs, you can change in the menu Plugins - InaSAFE - Minimum Needs Configuration.