Abstract: Because GIS administrators need to build web mapping applications without writing code, re-usable components were developed: a Server Object Extension (SOE) and an add-in for Esri's Viewer for Silverlight. Without writing any code, a mapservice was configured to serve NHD information from the National Atlas, and extended with the SOE for tracing capabilities. Using the Builder tool, a web map app was built that included the Trace Tool add-in, and configured with a url to the NHD mapservice SOE.
Developed by Kirk Kuykendall, AmberGIS
NHD data downloaded from the National Map.
Base layer is from ArcGIS.com
Amazon EC2 hosts the data and the application.
These tools are intended to be used by GIS administrators who need to build web apps that provide network tracing.
I had to download the NHD and publish it as a map service and configure it with a Server Object Extension (SOE). It would make more sense if TNM had a process whereby SOE's could be vetted and published. That way people could analyze and trace without having to download NHD and publish as their own mapservice.
For example, it would be helpful to query the flowlines directly from this map service: http://services.nationalmap.gov/ArcGIS/rest/services/NHD_Large/MapServer/48
using trace tools instead of downloading the NHD and making a redundant mapservice just so it can be configured with the SOE.
On the client side, trace results can be further processed by other add-ins. This means GIS administrators can synergistically build apps, mixing and matching add-ins from different sources. Unlike arcmap where trace results are not very accessible, the trace results in a web client are stored as a graphics layer. Other add-ins could take the trace results and, for example, buffer it or do proximity searches against other map services.