DATA ENTRY AND PREPARATION
INTRODUCTION Spatial data can be obtained from various sources and can be collected from scratch, using direct spatial data acquisition techniques, or indirectly, by making use of existing spatial data collected by others. Direct data collection could involve field survey data and remotely sensed images, while paper maps and existing digital data sets fall under indirect sources. This topic discusses the collection and use of direct and indirect data collection with a view to prepare users of spatial data by drawing attention to issues concerning data accuracy and quality. A range of procedures for data checking and clean-up would be examined to prepare data for analysis, including several methods for interpolating point data. DIRECT SPATIAL DATA CAPTURE One way to obtain spatial data is by direct observation of the relevant geographic phenomena. This can be done through ground-based field surveys, or by using remote sensors in satellites or airplanes. Data which is captured direc...