Geospatial visualization of global satellite images with Vis-EROS

Abstract

Geospatial data visualization is significantly changing the way we view spatial data and discover information. On the one hand, a large number of spatial data, which carry extremely valuable information, are generated on daily basis. On the other hand, these data are not well utilized due to the lack of free and easily used data visualization tools. This paper describes a way of visualizing massive spatial data at no cost by utilizing publically available visualization tools like Google Earth. We illustrate our methods by visualizing a million global download requests for satellite images maintained by the Earth Resources Observation and Science (EROS) Center of U.S. Geological Survey (USGS).

Introduction

Data visualization is playing a more and more important role in representing and analyzing scientific data. A large amount of scientific data carries spatial or geographical information, e.g. the earth satellite image data collected by the U.S. National Aeronautics and Space Administration (NASA) and U.S. Geological Survey (USGS). Unfortunately, most geospatial data are not fully utilized due to the lack of free and ease-of-use geo-visualization tools. Developing user-friendly web-mapping services (e.g. Horsburgh et al., 2009, Iosifescu-Enescu et al., 2010) to facilitate access and analysis of large environmental datasets has emerged as an interesting research field.

In recent years, many interactive web-mapping services, such as Google Earth (http://earth.google.com), NASA World Wind (http://worldwind.arc.nasa.gov), and Microsoft Virtual Earth (http://www.microsoft.com/virtualearth), enable users to exploit geospatially visualized mashups that combine local datasets with the data available from external severs. These web-mapping services provide APIs that support HTML, Java and XML and allow developers to create custom applications. There has been a quick rise in the application of these mapping services to developing geo-visualization tools. For example, Zhang and Shi (2007) presented a web-mapping application based on a conference presentation of geographic location using Google Maps. Fisher (2007) developed Hotmap, a mashup visualization tool based on Microsoft’s Live Search Maps to visualize the number of downloads of imagery and understand the users’ interaction with the world. Wood et al. (2007) demonstrated a geo-visualization mashup case study using Google Earth for interactive synthesis of encodings generated by MySQL, PHP and LandSerf.

This research is motivated by the great needs of efficient and cost-effective geo-visualization tools for analyzing scientific spatial data. By using Google Earth, a web service (Vis-EROS) is developed to visualize the global download requests for satellite images maintained by the USGS Earth Resources Observation and Science Center (EROS). The software is developed by following some of the guidelines for effective data visualization in scientific publications, which was presented by Kelleher and Wagener, (2011). Specifically, the Vis-EROS web portal is created where users can quickly and easily evaluate relevant geographic information pertaining to download requests made within specified dates and visualize the nature of the requests based on various geographic properties. This radically improves the quality of information that can be discerned from the global user download patterns.