geographic_search.m
  Function for searching online data and downloading it.
  Retrieves all data within a bounding box defined by corner coordinates in lat/lon
  You may need to set the Java Heap size property in Matlab to a larger value
  (e.g. 256 MB or more) to download large files. The error message from
  urlread when Java runs out of memory indicates that the URL is bad or
  the connection is bad (i.e. the error message for too small of a heap
  size is misleading).