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INTRODUCTION CONTACT RESEARCH PUBLICATIONS |
Geographical Databases
What is a GIS?A geographical information system (GIS) is a computer-based database for storing, managing, manipulating and displaying data about things that exist or events that occur in space. In most cases the space being considered is the surface of the Earth, but it can range anywhere between a strand of DNA or a solar system. In other words, the key defining thing about these things or events is that they have a (geographic) location that is stored in the database along with their other characteristics that allow them to be visualised in the form of maps and the spatial relationships between them to be analysed. The Caversham Project has developed a spatial database using Arc/Info GIS software (developed by the Environmental Systems Research Institute). Spatial data in this database are organised into thematic layers (see figure) so that spatial features of the same type are stored together, e.g. Data concerning property boundaries are stored in one layer, street centrelines in another, etc. The layers remain linked by the geographic co-ordinates of the features stored in them so spatial relationships between features on different layers can still be analysed. What does it contain?Much of the work developing the spatial database for the Caversham Project has involved recreating the properties that existed during the time period in question. We have just completed reconstructing the 2,200-odd properties that existed the study area in 1922 (see figure). This process involved an initial reconstruction of legal land parcel boundaries for this period and assigning them (or portions of them) to properties based on legal descriptions of properties contained in valuation records for 1922 and descriptions contained in the Stones Directories of the time. Occasionally we also had to carry out title searches for properties we couldn't resolve from these sources. For each property we have recorded a unique identifier and street address. This allows us to integrate records in the spatial database with the other databases we have compiled, such as those developed from valuation books and electoral rolls. This lets us ask more complex questions about the structure of society in the study area. For example, we can produce maps showing the distribution of residential and commercial properties, highlighting those industries that are noxious, display all of the properties owned by a particular individual, show where the white-collar workers lived, or the correlation of property value with topographic characteristics such as altitude and aspect i.e. higher, north-facing properties may have a higher value if they were more attractive than low-lying, south facing ones. Most importantly we are interested in analysing and describing the spatial distribution of occupational structure and social class and to examine how the pattern of this distribution changed over time. Example output
A map of Caversham in 1922. |
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Last updated 4th November 2010. |
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