Using the InaSAFE Plugin

This document describes the useage of the InaSAFE ‘dock panel’ - which is the main interface for running risk scenarios within the Quantum GIS environment.

Note

In order to use the InaSAFE tool effectively, you should probably also read the Keywords System and Impact Functions documentation before you get started.

The InaSAFE Dock panel is the main way to interact with the tools that are provided in InaSAFE. After you have installed the InaSAFE plugin, the dock panel will automatically load in QGIS, appearing on the left hand side of the screen.

../_images/inasafe-dock-panel.jpeg

You can drag and drop the dock panel to reposition it in the user interface. For example, dragging the panel towards the right margin of the QGIS application will dock it to the right side of the screen.

../_images/docked-right.jpeg

There are 3 main areas to the panel:

  • the Questions area
  • the Results area
  • the buttons area

At any time you can obtain help in InaSAFE by clicking on the help buttons provided on each dock and dialog.

The Questions Area

The intention of InaSAFE is to make it really simple and easy to perform your impact analysis. The question area provides a simple way for you to formulate what it is you want to find out? All questions are formulated in the form:

If [hazard] how many [exposure] might [impact].

For example:

If there is a flood how many schools might be closed.

In order to answer such questions, the InaSAFE developers have built a number of impact functions that cover scenarios such as flood, tsunami, volcanic ash fall, earthquake and so on. You can read our impact function documentation to find out more information about the various Impact Functions implemented.

The formulation of these questions if carried out by loading layers into QGIS that represent either hazard or exposure scenarious.

  • A hazard (In the event of) may be represented as, for example, a raster layer in QGIS where each pixel in the raster represents the current flood depth following an inundation event.
  • An exposure (How many) layer could be represented, for example, as vector polygon data representing building outlines, or a raster outline where each pixel represents the number of people resident in that cell.

The impact function (Might) will combine these two input layers in a mathematical model in order to postulate what the impacts of the hazard will be on the exposure infrastructure or people.

By selecting a combination from the In the event of and How many combo boxes, an appropriate set of impact functions will be listed in the Might combo box.

You may be wondering how the InaSAFE plugin determines whether a layer should be listed in the In the event of or How many combo boxes? The plugin relies on simple keyword metadata to be associated with each layer. The keyword system is described in detail in Keywords System. Each layer that has a keyword allocating it’s category to hazard will be listed in the In the event of combo. Similarly, a category of exposure in the keywords for a layer will result in it being listed under the How many combo.

InaSAFE uses the combination of category, subcategory, units and datatype keywords to determine which impact functions will be listed in the Might combo.

The results area

The Results area is used to display various useful feedback items to the user. Once an impact scenario has been run (see next section below), a summary table will be shown.

../_images/scenario-results.png

If you select an impact layer (i.e. a layer that was produced using an InaSAFE impact function), in the QGIS layers list, this summary will also be displayed in the results area.

When you select a hazard or exposure layer in the QGIS layers list, the keywords for that layer will be shown in the Results area, making it easy to understand what metadata exists for that layer.

../_images/keywords-for-active-layer.png

The Results area is also used to display status information. For example, when a suitable combination of hazard (In the event of), exposure (How many) and impact function (In the event of) are selected, the results area will be updated to indicate that you can proceed to run the impact scenario calculation.

../_images/status-ready.png

While a scenario is being computed, the Results area displays the current progress of the analysis.

../_images/calculation-progress.png

Finally, the Results area is also used to display any error messages so that the user is informed as to what went wrong and why.

../_images/error-display.png

Note

At the bottom of error display you may see button like this: .. image:: ../../toggle-traceback.png If you click on this button, it will display a box which will contain useful diagnostic information which can be submitted as part of a bug report if you think the error was incorrect.

The buttons area

The buttons area contains three buttons:

  • Help - click on this if you need context help, such as the document you are reading right now!
  • Print... - click on this if you wish to create a pdf of your impact scenarion project. An impact layer must be active before the Print... button will be enabled.
  • Run - if the combination of options in the Questions area’s combo boxes will allow you to run a scenario, this button is enabled.

Data conversions when running a scenario

When running a scenario, the data being used needs to be processed into a state where it is acceptible for use by the impact function. In particular it should be noted that:

  • Remote datasets will be copied locally before processing.
  • All datasets will be clipped to the intersection of the hazard layer, the exposure layer and the current view extents.
  • All clipped datasets will be converted (reprojected) to Geographic (EPSG:4326) coordinate reference system before analysis.

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