Interface - NRCS (AWDB)

USDA NRCS NWCC AWDB (Air-Water DataBase) Web Services - Stations GIS Interface

AWDB is a web-based information service that provides methods for programmatically accessing metadata (elements, units, stations, etc.), data, 30-year normals, and water supply forecasts. For more information about AWDB, please visit http://www.wcc.nrcs.usda.gov/web_service/awdb_web_service_landing.htm. AWDB provides updated stations data (including SNOTEL, snow courses, coop, and USGS gauge stations) that are used in BAGIS for basin analysis. However, these data are not in a GIS format that can be used in GIS software directly. PSU CSAR developed automated scripts that connect to AWDB and use the extracted station metadata to generate GIS layers for direct use in GIS. The scripts run every Monday at 3 am and generate 8 web services for mapping and analysis uses. There are 4 station service categories: co-op stations (AWDB_COOP), SNOTEL stations (AWDB_SNTL), snow course stations (AWDB_SNOW), and USGS gauge stations (AWDB_USGS). Each station type has one web mapping service (MapServer) and one web feature access service (FeatureServer) (see Figure 1 below). Web mapping services are used mainly for mapping purposes and support layer overlay (or mashup) and basic attribute query. Web feature access services are ESRI ArcGIS-specific web services that allow direct access to features in vector layers in ArcMap. Individual features can be used in ArcGIS spatial analysis.

Figure 1. AWDB stations web services on PSU CSAR GIS server.

Users can access CSAR Bagis GIS server's ArcGIS REST Services directory at http://bagis.geog.pdx.edu/arcgis/rest/services. If you want to use these services in ArcGIS, please follow the instructions below. The instructions use Web Feature Access Service as an example. Please note that only ArcGIS 10.1 or later can access web feature access services on an ArcGIS Server.

Connect to PSU CSAR ArcGIS Server in ArcGIS

• • Start ArcMap and open ArcMap Catalog (Figure 2). Double-click on the "Add ArcGIS Server" item in the GIS Servers container. Select "Use GIS Services" when prompted in the dialog window that appears (Figure 3).

Figure 2. Figure 3.

• • Enter "http://bagis.geog.pdx.edu/arcgis/services" in the Server URL field (Figure 4), leave all other fields blank, and click Finish. The Catalog dialog window refreshes itself and bagis server appears in the catalog. Click on the plus (+) sign next to the folders to expand them. There are 8 services in the AWDB folder. The first one is the web mapping service (MapServer) for co-op stations. The second one is the web feature access service (FeatureServer) for co-op stations (Figure 5).

Figure 4. Figure 5.

Add a web feature access service to ArcMap and query its attributes

• • Users can drag and drop a web service from a GIS Server to a map layout in ArcMap, as what they would do with other local feature classes. They can change the symbols for the web service layers and open the attribute tables of web feature access services to perform attribute or spatial query (Figure 6).

Figure 6.

Use a web feature access service in analysis

• • Users can also use these web feature access service layers in spatial analysis. Figure 7 illustrates the use of a web service in the Buffer tool.

Figure 7.