All, For App Engine to be considered a platform for custom GIS (outside of what is current possible with Google Maps) we need to have a robust mechanism for spatial queries. This is provided by the Java Topology Suite (JTS). My initial reference application for JTS on App Engine can be found at http://giscloud.appspot.com (follow the links to the source code).
The reference application, however, does not employ a spatial index. This is problematic if our application needs to make repeated spatial queries on large sets of geometries. Spatial indexes are typically stored in the file system of the application in question, but under App Engine we have limited use of the file system. Offline building of the index also presents some problems. The only realistic option I have discovered so far is to persist the spatial index in the App Engine datastore, but the datastore expects all objects to be serializable and the current JTS indexes are not. Thus, JTS needs to be modified to permit serializing indexes. Here is my initial foray into making the STRtree spatial index serializable: http://code.google.com/p/giscloud/wiki/SerializedSpatialIndexes Best regards, Stuart Moffatt Ph.D. student ~ http://home.gwu.edu/~sfm Crisis, Emergency and Risk Management http://www.gwu.edu/~icdrm --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en -~----------~----~----~----~------~----~------~--~---
