The USC Geoportal is a web application serving both geospatial information providers and users that enables the discovery and use of geospatial resources, including datasets, rasters and services, via the Internet.
The geospatial information providers use geoportals to organize and publish descriptions (metadata) of their geospatial information, whereas the geospatial information consumers will use geoportals to rapidly discover, preview, and retrieve geospatial data, which will often incorporate multiple themes (roads, administrative boundaries, elevation, parks, etc.) drawn from multiple repositories.
Geoportal website access
The USC Geoportal website is directly accessible from the USC network on campus. Anyone on campus wishing to access this application using a mobile device such as a laptop, tablet PC or a smart phone needs to first establish a secure VPN connection to the USC network. View instructions for connecting via VPN.
Those not on the USC campus can access the USC Geoportal web application by first logging in using your USC credentials and establishing a successful VPN connection. You then will be redirected to the USC Geoportal website.
Compatibility with ArcGIS 10.1
The map services and spatial data that can be retrieved from the USC Geoportal were pre-processed using ArcGIS version 10.1. This means that any user wanting to utilize the map services in ArcMap will need ArcGIS version 10.1. Similarly, a user wanting to download data in a geodatabase format needs to have ArcGIS version 10.1 to display data in ArcMap or ArcCatalog. There is also the option of downloading the data in the shapefile format which can be accessed in any version of ArcGIS and via a variety of additional software platforms that can view shapefiles. Similarly, a user can choose to view map services in the integrated Map Viewer (accessible via the Launch Map Viewer menu item) or in ArcGIS Explorer and Google Earth software (both free) in the event ArcGIS version 10.1 is not available.
We have created several short videos to help with the discovery, preview, and retrieval of geospatial datasets. These videos run 5-10 minutes and can be viewed on the Demos page of the USC Geoportal website.
Currently over 60 layers are available for download on the USC Geoportal. A detailed list of data layers can also be viewed here. The search keywords accept a wildcard * if using a keyword search for data. When a data download request is submitted on the Geoportal website, the web server sends this request to an ArcGIS Server, and the ArcGIS server runs a geoprocessing web service that actually clips the data to the extent specified by a user.
Currently just one ArcGIS server handles data download requests, which allocates each task a maximum of 20 minutes of processing time. For tasks that exceed this time limit, the server will send a message on the data download page informing the user that the download task failed due to a time-out limit. In such a case, the user can reduce the number of layers requested for data download or can reduce the spatial extent of the shape for which data is requested and resubmit the download request.
Some of the datasets, such as building outlines or parcels for Los Angeles County, are large datasets, and typically they require a longer processing time for downloading. If a user requests large quantities of geospatial data and the server times-out while processing the request, please contact the Spatial Sciences Institute via the feedback form, and request the data directly.
When downloading raster data, note that the selection of different raster data formats imposes restrictions on allowed data names for downloaded data. For example, if a user choses GRID as the data download raster format, the downloaded rasters will have an abbreviated name containing 10 characters derived from the original dataset name. If a user plans to view downloaded raster data in ArcGIS version 10.1 or higher, a geodatabase is recommended to complete this task, since it allows for longer dataset names.
All of the data have been published as live map services. A user therefore can preview all of the data by viewing the relevant map service in the integrated Map Viewer or in the software platform of choice (i.e. ArcMap, ArcGIS Explorer, or Google Earth) before retrieving the datasets themselves. Map services are essentially maps published as a web service, and a single map service may contain more than one data layer – the map service entitled Los_Angeles_Region_Contours, for example, incorporates the following data layers: LAR_Contours_250FT, LAR_Contours_2FT, LAR_Contours_10FT, and LAR_Contours_500FT. A user can browse through various map services by accessing the Browse page of the Geoportal website. The map services are cross-referenced by ISO topic categories on the USC Geoportal website.