Web Mapping Services
The objective of this assignment was to illustrate how existing data layers and maps can be integrated into an ArcMap project to enhance and/or complement the data presentation. The proliferation of online GIS data has produced large amounts of information that can be used as a base layer for map presentation. These existing map layers can help provide more information, provide a better frame of reference, and help the customization of the data for the target audience. Two of the popular sources of existing base map layers were explored in this exercise, Bing maps and ESRI ArcIMS servers.
This project was part of the requirements for GIS 520, Advanced Spatial Analytics. The data used in this assignment was downloaded from two differenct sources. The aerial base layer was retrieved from Bing Maps and the Wake County jurisdiction boundary map was retrieved from the Wake County ArcIMS server.
The aerial layer from Bing maps was chosen as the base layer for this map assignment. The road and hybrid layers provided nearly the same data, but contained labels and text for major roads, cities, and prominent topography. While any of the layers would have worked, the aerial was best suited to illustrate the primary objective of this map. A Wake county jurisdiction boundary layer was selected from the Wake count map server as the top layer. Other options were considered, but Wake county provides a much more comprehensive set of data than other counties within North Carolina, and was the easiest to work with to illustrate the layering concepts.
The map below illustrates the use of the Bing map aerial layer as the base layer for the map. The suggested projection was used when adding the Wake county data to the map, to ensure both layers were spatially aligned. The intention of the map was to show the location of Wake county in relation to the Outer Banks of North Carolina. The perspective of the map was selected to show the most detail of the aerial layer while allowing the Wake county jurisdictions to be visible. However, the display of the jurisdiction labels on the map are not very legible and should be removed or a different layer could be selected that only represented the Wake county boundary.
The use of data layers from existing online web mapping services can be used to complement or enhance almost any map presentation within ArcMap. Understanding what data is available and where to locate it, is key skill for any GIS professional. Having a library of data sources such as the Bing map layers and the NCSU GIS Library NC County ArcIMS site listing, is an invaluable resource and time saver when these existing data sets can be used in an analysis. One of the primary uses of such data would be for showing spatial relationships between the primary data being studied and how it is related to a larger geographic area that may be more familiar with the targeted audience.