# Keywords System

This document describes the purpose and usage of the InaSAFE keywords system.

See also

Please also refer to the documentation on the keywords Wizards and the keywords editor which are tools to help you to create keywords files.

## Purpose

The keywords system is used by the Impact Functions to determine the nature of the input layers that have been passed to them.

Each input GIS dataset used by InaSAFE needs to have an accompanying keywords file. The purpose of the keywords file is to provide additional metadata needed by the impact functions. For example, the keywords file will indicate whether a given dataset should be treated as a hazard or an impact layer. It is also used to indicate the context of the layer (e.g. “it’s a flood layer”, “it’s an earthquake layer”).

By convention and expectation, the keywords file should be named with the same base name of the GIS datasource it accompanies. For example a flood dataset saved as

`C:\gisdata\flood.tif`

would need to have an accompanying keywords file saved as:

`C:\gisdata\flood.keywords`

Note

We recommend to avoid using spaces in your file names and file paths!

The InaSAFE QGIS plugin provides an editor for these keywords. The purpose of this document is to describe the keywords editor and to provide guidelines as to the use of keywords.

Note

Currently keywords are not validated by the library. This means if you for example misspell a keyword, use the wrong letter case (e.g. upper case instead of lower case) or provide the wrong keyword for the context (e.g. provide a subcategory of flood to an exposure category), the system will not be able to determine what to do with the file. For that reason you should follow the guidelines below carefully to ensure you have entered your keywords correctly.

## Guidelines

In this section we lay out the guidelines for keyword usage.

### Category

Every dataset should have a category assigned to it. Category should be written in lower case.

Key | Allowed Values
--- | ---
category | hazard
category | exposure
category | aggregation

Example keywords file entry

    category: hazard

### Subcategory

The selection of a subcategory value is dependent on the category:

Valid subcategories for category ‘hazard’:

Key | Allowed Values
--- | ---
subcategory | tsunami
subcategory | flood
subcategory | volcano
subcategory | earthquake

Where tephra is volcanic ashfall.

Valid subcategories for category ‘exposure’:

Key | Allowed Values
--- | ---
exposure | population
exposure | structure
exposure | road

Example keywords file entry

    category: hazard
    subcategory: flood

### Units

The units keyword is used to indicate the metric or imperial units represented by each data entity (a grid cell or a vector feature) in a layer.

Example keywords file entry:

> > Key | Allowed Values (pre InaSAFE 2.1) | Allowed Values (>= 2.1)
> > --- | --- | ---
> > units | m | metres_depth
> > units |  |
> > exposure | road |
> > hazard |  |

> category: hazard subcategory: flood units: m

In the above case there is a soft constraint to use a value for units of m, feet or wet/dry as defined by the table below because the subcategory is ‘flood’. The following are the allowed units which are dependent on the subcategory defined.

Valid subcategories for subcategory ‘tsunami’ or subcategory ‘flood’:

Key | Allowed Values
--- | ---
units | m
units | wet/dry
units | feet

In the case where the units are m (meters) or feet, the input dataset should be a raster layer where each cell in the raster represents a depth in the units specified.

In the case of wet/dry, the input dataset needs to be a vector polygon layer. Any area that is inside a polygon is considered ‘wet’ and any area outside of a polygon is considered to be ‘dry’.

Valid subcategories for subcategory ‘volcano’

Key | Allowed Values
--- | ---
units | kg2/m2

In this case the dataset should be a raster layer where each cell represents the kilograms per meters squared of ash fall on that cell.

Note

‘units’ and ‘datatype’ (described below) should be considered to be mutually exclusive - i.e. they should not both be present in any given keywords file.

### Datatype

The data type keyword indicate what kind of geospatial data is represented (Numeric, Polygon, Line, Point).

## Assumptions

The following assumptions are made about keywords, which may or may not be programmatically enforced by the InaSAFE library and GUI:

- There should only be one keyword for a given key in the keywords file.
- Keywords for category are enforced to be one of ‘hazard’ or ‘exposure’ by the GUI.
- All keywords should be in lower case, without spaces with the exception of ‘Title’ whose value may contain both spaces and mixed case letters.
- Values for keywords should generally be lower case, with the exception of datatype values may be in upper case (e.g. MMI)
- Keys and values should not contain colons. In the keyword editor, any colons will be replaced with a full stop character.
- All other Keywords and values that do not fit the above domain lists may be used but they may produce undesired results.

## Translations

Although InaSAFE is available in different languages, the ‘key’ in the keywords files should always be written in english.

## Keywords for remote and non-file based layers

If you are using a PostgreSQL, WFS, Spatialite or other non-file based resources, you can still create keywords. In these circumstances the keywords will be written to a sqlite database - by default this database is stored as `keywords.db` within the InaSAFE plugin directory root.

You may wish to use a different location for the `keywords.db` keywords database - you can configure this by using the InaSAFE options dialog. The options dialog can be launched by clicking on the InaSAFE plugin toolbar’s options icon (as shown below) or by doing Plugins ‣ InaSAFE ‣ InaSAFE Options.

Selecting the options icon

When the options dialog is opened, the keywords database path can be specified under the tab Advanced using the keyword cache for remote datasources option as shown below.

Path to options database

Note

1. Support for remote and non-file based layers was added in InaSAFE version 0.3.
2. The database can be opened using a sqlite editor such as sqliteman, but the data in the keywords table is not intended to be human readable or edited. The table columns consist of an MD5 hash based on the URI for the datasource (typically the database connection details) and a blob which contains the keywords as a pickled python dictionary.

See the Options document for more information about the InaSAFE options dialog.

## Sharing your keywords cache

In theory you can place the keywords file on a network share and create a shared keyword repository in a multi-user environment, but you should note that the layer URI hashes need to be identical in order for a layer’s keyword to be found. This means that, for (contrived), example

    connection=postgresql,user=joe,password=secret,resource=osm_buildings

would not be considered the same as

    connection=postgresql,user=anne,password=secret,resource=osm_buildings

since the user credentials differ, resulting in a different URI. To work around this you could create a common account so that every user will effectively use the same URI to load that layer e.g.

    connection=postgresql,user=public,password=secret,resource=osm_buildings

For certain resources (e.g. ArcInfo coverages, Spatialite databases) where the keywords cache is also used, you should take care to use a common mount point or network share to access the data if you wish to successfully hit the cache with the layer’s URI. For example you could have all users mount your data to the same place. Under Unix like operating systems this could look something like this:

`/mnt/gisdata/jk.sqlite`

Under Windows you could always the same drive letter and path the to share e.g.:

`Z:\gisdata\jk.sqlite`

## Getting help

If you need help using the keywords editor, you can click on the Help button at the bottom of the dialog and this page will be displayed.