Developing geoprocessing service for Cropland Data Layer thematic map creation

NASS Cropland Data Layer (CDL) data have been widely used in many business, research and academic areas. This valuable geospatial data has been accessible and disseminated through CropScape - a web-service based online geospatial application. Web geoprocessing services had been required and developed in CropScape to visualize, navigate, analyze, and download the CDL data in an open standard. Especially, an online thematic map generating function had been required by many users to produce, print or share CDL maps of an area of interest without using any mapping software. This paper is concerned with how to develop a new Web geoprocessing service, which uses API functions of Apache Axis2, Geospatial Data Abstraction Library and Cairo graphics library to generate the thematic map of CDL in PDF format with the preferred settings. The resulting geoprocessing service enabled CropScape to create the CDL thematic map interactively, significantly reduced operational resource and cost, and greatly improved efficiency and CDL data presentation.