13 - MAINTAINING SPATIAL DATA

Summary

Introduction

The most valuable (non-human) resource that any organisation possesses is its data. Hardware and software are easily replaceable but the loss of data can be catastrophic for an organisation. Information loss, whether full or partial, is easily avoided through the routine taking of backups and the storage of data off-site. As there is plenty of readily available information on how best to implement a backup and data-recovery procedure, we do not consider it in any detail in this book. What is less obvious, particularly to those new to GIS and digital data, is the similarly important task of data maintenance. Consider, for example, the following three scenarios:

• An employee in a cultural resource management (CRM) unit is assigned the task of updating site locations from newly acquired GPS data. How should the fact that a few site locations have been updated be documented and where and how should the old data be stored?

• An aerial photograph of a portion of landscape has been rectified and georeferenced, and is ready to be used to delineate features of archaeological significance. How and where should information about the degree of error in the georeferencing be documented? Where and how should the errors for the newly digitised archaeological features be documented?

• A research student is collecting data on soil types for Eastern Europe from several different national agencies that each have different scales and recording systems. How is this student able to search and compare and ultimately integrate datasets in a manner that ensures the data will be appropriate for his/her needs?