Least-cost-path Analysis DigitalGlobe AES 8-meter Precision digital surface model and CountrySphere imagery in Chile
Viewshed Analysis DigitalGlobe AES 4-meter Precision digital surface model and CitySphere imagery of Dunedin, New Zealand
3D View DigitalGlobe AES 8-meter Precision digital surface model and CountrySphere imagery in Chile
NATALIE CUTSFORTH Client Solutions Executive Idea Denver, Colo. www.idea.com
Advances in technology, data storage and distribution have allowed analysis of Earth observation data to be placed more firmly in the hands of the decision makers than ever. Satellite elevation data created from stereo imagery can be acquired anywhere in the world; accuracy of data collected is higher than ever; and large datasets can be processed through cloud computing, increasing speed of results.
Engineers do not have to be geospatial experts to review least-cost-path options for placement of a pipeline. Community participants don’t have to understand the science behind line-of-sight analysis to determine the best location for placement of broadband towers to provide coverage in their town. Military personnel can assess the best ground approach en-route utilizing secure Web-based elevation data tools with imagery.
Until recently, the size of higher accuracy elevation data, the expertise required to write algorithms for analysis, and the time needed to process these analyses kept the decision maker a step or two away from the information required to move forward. Cloud processing, in conjunction with Web-based geospatial analysis tools, allows development of simple interfaces for users who do not need to own any software or hardware beyond a desktop computer or mobile device with internet access, nor to store and maintain their own data.
The feasibility of this virtual analysis approach has been demonstrated utilizing Esri’s (Redlands, Calif.) ArcGIS Server Web interface within the Amazon EC2 Elastic Compute Cloud (Seattle, Wash.), with DigitalGlobe’s (Longmont, Colo.) Advanced Elevation Series (AES), alongside other Web services such as satellite imagery, publically available elevation data, and basemap data. A fully cloud-based hardware, software and data service, the application was developed by Idea (Jacksonville, Fl.), applying the "one question, one answer" design methodology coined by Geographic Information Systems (GIS) practice executive Brady Hustad.
The question that stimulated this project was, "What would make it easier for people to use elevation data?" The answer: intuitive Web applications that answer focused questions for specific users where they don’t have to concern themselves with the hardware, software and data management. Trusted experts in their organization or in service-providing organizations design deeply analytical but simple-to-use geoprocessing tools based on their users’ workflow. They insure that the data accuracy in their system is appropriate for the use, then utilize Web services for high-speed processing of large-scale datasets in the cloud.
"DigitalGlobe’s constellation collects over 2.4 million km2 on a daily basis. The global reach of the constellation has enabled DigitalGlobe to deliver Advanced Elevation Series products on every continent, including Antarctica. As WorldView-1 and WorldView-2 satellites are able to slew 200km in 10 seconds, they are preferred platforms for capturing stereo data – the raw materials needed for development of AES elevation products. And with the expertise in planning and collecting imagery, DigitalGlobe has cultivated and developed expert processing to deliver quickly large expanses of elevation and orthorectified imagery," states Stuart Schwartz, elevation product manager at DigitalGlobe. To further the availability of this type data, users benefit by accessing it as a Web service and integrating it into a meaningful question/answer context.
Higher accuracy means larger data – an increased number of pixels for an area of imagery or elevation data, such as the 2-, 4-, and 8-meter AES digital terrain and digital surface models. In the past, analysis of large datasets was limited to desktop processes, as Web-based tools are limited by bandwidth. Now cloud computing harnesses the capacity of server farms with much greater extensibility than a typical company can justify investing in their own infrastructure, and takes away the heavy lifting from the internet interface for geoprocessing, while quickly returning an answer to the users’ queries.
On the ground, users can select a point on the map referencing imagery, choose the accuracy of elevation data if necessary for their application, and execute a process that returns the footprint of coverage generated from a cell tower placed at a certain location, using elevation data in the analysis. More accurate data provides more exact analysis results. Taking this line-of-sight study into a 3D view adds critical information to the decision-making process, such as obstacles which need to be considered that would alter the placement of the towers. See Figures 1-3.
Intuitive Web applications that answer focused questions for specific users have the greatest impact. We’ve achieved our industry’s highest aspiration of increasing the footprint of Earth observation data, when people in any role are using GIS to get their jobs done without being aware of it. Satellite remotely sensed imagery and elevation data are at the foundation of this marriage of technology, science and human decision-making processes.
Editor’s Note: All imagery is courtesy of DigitalGlobe.