ENVIJagwireServer::Query

This method returns a hash table of raster datasets available on the Jagwire server.

Example

; Start the application

e = ENVI()

; Open the Jagwire Server

jagwireServer = ENVIJagwireServer('https://myserver/jagwire', $

  USERNAME='myusername', PASSWORD='mypassword')

; Get a list of rasters within Florida

listings = jagwireServer.Query(Hash('bbox',[-88.0, 24.0, -79.0, 31.0]))  ;xmin, ymin, xmax, ymax

; Print the list and its properties

print, listings

; Query the world

listings = jagwireServer.Query(Hash('bbox',[-180, -90, 180, 90]))  ;xmin, ymin, xmax, ymax

; Print the URIs

print, listings.Values()

; Open a raster from the query

raster = e.OpenRaster(listings['myDataset'])

; Search for all raster data on the minute of May 20th 2013 18:36z

time = ENVITime(ACQUISITION='2013-05-20T18:36:00Z')

listings = jagwireServer.Query(Hash('time', time))

; Search for all raster between May 20th 2013 00:00z and May 20th 2014 00:00z

start = ENVITime(ACQUISITION='2013-05-20T00:00:00Z')

end = ENVITime(ACQUISITION='2014-05-20T00:00:00Z')

listings = jagwireServer.Query(Hash('time', [start, end] ))

; Search for all raster data before May 20th 2013 18:36z only in Florida

end = ENVITime(ACQUISITION='2013-05-20T18:36:00Z')

listings = jagwireServer.Query(Hash('time', [ENVITime(), end],  $

  'bbox', [-88.0, 24.0, -79.0, 31.0] ))

; Return and print a basic list of raster properties for each dataset

listings = jagwireServer.Query(/METADATA)

print, listings

Syntax

Result = ENVIJagwireServer.Query([, Filter] [, Keywords=value])

Return Value

This method returns a hash table of value pairs (with dataset name and URI) that are available in the Jagwire server.

Arguments

Filter

A hash table of name value pairs to filter results. Jagwire accepts the following filters:

bbox: A four-element array of floating-point or integer values containing the latitude and longitude coordinates of the bounding box, in the order [xmin, ymin, xmax, ymax]. Only raster datasets within this boundary will be returned.
time: A one or two element array of ENVITime objects containing the start and end times. Only raster datasets within this time range will be returned. If only one ENVITime object is set, raster datasets within the nearest minute of the time object are returned. Setting a null ENVITime object for either the start or end time will set an infinite start or end time.

Keywords

ERROR

Set this keyword to a named variable that will contain any error message issued during execution of this routine. If no error occurs, the ERROR variable will be set to a null string (''). If an error occurs and the routine is a function, then the function result will be undefined.

When this keyword is not set and an error occurs, ENVI returns to the caller and execution halts. In this case, the error message is contained within !ERROR_STATE and can be caught using IDL's CATCH routine. See IDL Help for more information on !ERROR_STATE and CATCH.

See Manage Errors for more information on error handling in ENVI programming.

METADATA

Set this keyword to return a hash table of metadata listings, where the metadata listing is a hash table that contains basic name/value pairs for Jagwire raster metadata. The following are the values:

URI: A scalar string denoting the fully-qualified URL path to the Jagwire OGC WCS dataset.
NCOLUMNS: Number of columns.
NROWS: Number of rows.
NBANDS: Number of bands.
DATA_TYPE: If the TYPE is a RASTER, this returns an integer or string specifying the ENVIRaster DATA_TYPE. If the TYPE is a VIDEO or VECTOR, then this is null.
TYPE: Type of dataset returned from the query. It can be RASTER, VECTOR, VIDEO, POINT_CLOUD.
ACQUISITION: ISO standard date.
DESCRIPTION: A string, if a description exists.
EXTENT: An 8-element array of doubles for the four corners of the image.

A null value is set if any properties do not exist.

API Version

4.2

Version History

ENVI 5.3

Introduced