ABSTRACT
The chapter on GIS operations provides a primer on spatial data manipulations as implemented in the GeoDa software. Several important concepts related to projections are covered, such as a geodetic datum, latitude and longitude decimal degrees, EPSG code, universal transverse Mercator (UTM) projection as well as how reprojection is implemented in an intuitive manner in GeoDa.
Various geometric concepts are reviewed, including the notion of mean center, centroid, tessellation, Thiessen polygons, a minimum spanning tree (MST) and associated Primm's algorithm.
An important feature in GeoDa is how to handle multiple data layers and the associated operation of aggregation and dissolution (dissolve). This builds on the fundamental point in polygon operation through a spatial join and allows the computation of the number of points within a polygon and the assignment of a polygon identifier to a point layer.
