FAQs – Digital Research Services (GIS, Data Visualization, Digital Humanities) – Research Guides at University of Houston

Batch geocoding is the calculation of multiple addresses into their corresponding X and Y coordinates for easy displaying within GIS. While you can create an Address Locator in ArcGIS Desktop using reference data, the corresponding results will be based on the quality of the reference data used. This FAQ will describe two free batch geocoders that operate externally of any GIS application and return the latitude and longitude coordinates. There are two types of relevant table structures: Cross-Tabulation and Unpivot. The cross-tabbed structure is the most versatile, allowing for all functions that control a single Tableau visualization object, or multiple objects but without the ability to change attributes. The Unpivot structure is required to control multiple Tableau objects with the ability to change attributes. It is possible to combine these two table structures within a single table. This can be done by unpivoting a table and then merging the cross-tabulated attributes based on a key identifier field. The UH Libraries created a Python script that will automatically convert a standard cross-tabbed table to a hybrid cross-tabbed/unpivoted table from a source .CSV file. Please note that the script requires both the Python standard library and the Python Data Analysis Library (PANDAS), which is not included in the standard Python installation. Either download and install Pandas or use Portable Python 2.7, which comes packaged with PANDAS and does not require administrative computer rights to download and use. Georeferencing is aligning raster geographic data to a known coordinate system. In other words, positioning an geographic image to its correct location. (See Fundamentals of georeferencing a raster dataset). Vectorizing (also known as digitizing) is the process of converting raster elements into vector features. (See What is editing?) In ArcGIS Desktop, all georeferencing tools are stored within the Georeferencing Toolbar. This toolbar is hidden by default, so to view it you must select Customize/Toolbars/Georeferencing. In ArcGIS Desktop, the batch vectorizing tools are stored within the ArcScan Extension and the corresponding ArcScan Toolbar. Both are disabled by default. First, enable the extension by clicking Customize/Extensions and click the check-box next to ArcScene. Secon d, enable the toolbar by selecting Cusotmize/Toolbars/ArcScan. OpenStreetMap street and road files are veru usefuil for generating a network for areas where we do not have access to superior data. Network analysis is useful for transportation logistics, driving directions, drive time, drive distance, etc. Source.

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Last Modified: April 23, 2016 @ 8:01 am