Shapefiles
Touchstone and Touchstone Re support various shapefiles. The shapefiles spatially describe geometries such as points, lines, and polygons, which represent geographical features such as the epicenter of an earthquake, hurricane storm tracks, wind speed footprints, and state boundaries.
Note:
The data conversion examples used in the topic are based on the use of Esri's ArcGIS tools for converting the GIS files. However, you can use other GIS tools to prepare the GIS files for importing spatial data into Touchstone, such as: QuantumGIS (QGIS) and GDAL/OR (command line only).
A shapefile is a simple, non-topological vector format for storing the geometric location
and attribute information of geographic features. You may have your own surveyed flood or
earthquake data that has been saved in a shapefile format. A valid shapefile includes
several component files that contain geometric and attribute data. The following component
files are required and must be stored in the same project workspace.
| Component file | Description |
|---|---|
| SHP | The main file, which you select during the import process. This file contains information about the shapes (geometries) and locations of geographic features. |
| DBF | The database table that stores the attribute information for each shape in the shapefile. For example, this file could contain place names, latitude and longitude coordinates, magnitudes for earthquake objects, and wind speeds for hurricane-related objects. |
| SHX | The positional index of the feature geometry (the SHP file) that supports quick seeking forwards and backwards. |
Usage notes
- For each component in the shapefile, the maximum size is two gigabytes.
- The base name of the required files must be the same (e.g. USstates.shp, USstates.dbf).
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There are several ways that you may want to use imported shapefiles, for example:
- Polygons for specific hazard zones or areas, such as Florida Wind Mitigation Zones.
- Polygons for boundaries, such as territories or administrative areas.
- Polygons that identify the area or footprint affected by a given event, such as those included in our ALERT posts for the Oklahoma tornadoes, European floods, and Colorado fires. (Our ALERT worldwide provides recent catastrophe information and provides you with speedy access to posted event sets.)
- Polylines for measuring the distance to specific hazards (fault lines or coastlines) or events, such as for measuring events such as hurricane storm tracks.
- Points for measuring the distance to specific hazards or events, such as to the position of an earthquake's epicenter, or to terrorism events.