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Site Analysis Summary Site Analysis Operation Census Tract Demographics Geodemographics WebCourse |
Site Analysis with CommunityViewer -- analyzing characteristics of site locations: census tract demographics This section provides an overview of how the CommunityViewer software can be used for site analysis. The map in the following site analysis view shows a thematic map of median household income by census tract for the Tulsa, Oklahoma area. Tracts are shaded by colors for median household income as shown for the data value intervals in the legend panel (at left). At the same time, the SiteAnalysis operation has been used to draw a circle with a 2-mile radius at the location labeled Site 2. Data on the number of housing units by value in tracts partly/wholly located with the 2-mile circle are shown in the panels at the right. 
Application Objective. The next example might apply to the analysis of the characteristics of several alternative (or even one) sites that might be selected to develop a set of new housing units. The developer is interest in knowing how many housing units there are in a site that is roughly with 2-to-3 miles of the prospective building location. In addition, the developer wants to know how many of these housing units have a value in the $175,000 to $200,000 range. Site Analysis Summary. The upper right Site Analysis Summary shows that there are 21 tracts included in the analysis. The aggregate number of housing units for each category of housing value is shown in the same panel. The list of tracts that are partly/wholly contained in the 2-mile radius are shown in the listbox at the lower right. There are 16,088 housing units (summing for all tracts in the 2-mile site radius) as shown for item 'H074001'. Table H074 contains 25 data items/fields as shown in the following graphic. The procedure to download and integrate these types of demographics is described in detail in the tutorial Census Tract Demographics. 
Shorthand table/item names follow nomenclature, such as H074001, used (in the case of Census-sourced census tract demographics) in the summary report follow the Census naming convention. The details of correspondence between the item descriptor and longer description is shown in the Excel file downloaded to the user's computer. The following graphic shows a portion of the Excel file. Item 'H074001' is the shorthand (item descriptor) for 'Specified owner-occupied housing units: Total'. 
Referring back to the analysis objectives (described above), the answers to the developer's questions are answered by this site analysis. Of the 16,088 housing units in the study area, there are 41 units in the $175,000 to $200,000 range. This value is shown in the summary report for item H074018. 
Site Analysis Operation. Start CV and open the project to be used. Click on the layer to be used for the site analysis in the legend panel, making it the active layer. This would normally be the county or state by census tracts layer that has been loaded with the demographic subject matter for the analysis. Invoke the Site Analysis operation using Tools>SiteAnalysis. A verification message appears to confirm that the correct layer is active. A prompt/input box appears 'Geographic Field to Query'. The default value is TRACT which is the standard name for census tract demographic layers. This must be a valid geocode field name in the layer to be analyzed. A prompt/input box appears 'Statistical Table to Summarize'. The default value is PCT049 which is the name for the Summary File 3 Table PCT 49. The table referenced must have been loaded into the layer to be analyzed. In the example shown on this page, the value entered was H074. The message 'Click on location, drag to desired radius, and release'. When this action is performed, the Site Analysis report is generated immediately. This operation may be applied repeatedly. When the mouse button is released a transparent circle is drawn. All areas in the active layer that are partly/wholly contained in this circle are selected. Areas that are selected are shown by a cross-hatching pattern. A point/marker layer, such as the 4 sites example used earlier in this section, is not required. However, for most analyses such markers will make analyses easier. goto top |
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