Open topic with navigation

IDLnetOGCWCS::GetCoverageOfferingBriefs

Syntax | Return Value | Arguments| Keywords | Examples | Version History | See Also

The IDLnetOGCWCS::GetCoverageOfferingBriefs function method provides access to the coverage offering briefs that were returned and parsed by the IDLnetOGCWCS::GetCapabilities method. You can return all coverage offering briefs or a subset of the briefs, which can be useful when:

• A large number of briefs would require significant amounts of memory to return all of them at a single time
• A user interface needs to display a subset of the available items

This method will throw an error if the GetCoverageOfferingBriefs call fails.

Note: Use IDLnetOGCWCS::GetServiceSection to return information related to the service section of the coverage offering briefs.

Syntax

Result = Obj->[IDLnetOGCWCS::]GetCoverageOfferingBriefs ([, COUNT=variable], [, NUMBER=value] [, INDEX=value])

Return Value

The return value is an array of structures containing one or more coverage offering briefs. Use the COUNT keyword to verify that briefs are available since the returned value can be zero when briefs are not available. All elements are strings unless otherwise noted.

Arguments

None

Keywords

COUNT

Set this keyword to a variable that will contain the number of brief structures returned in this method’s structure array. This value can be zero.

NUMBER

Set this keyword to the number of coverage offering briefs to return. If this keyword is not set, all briefs will be returned minus the number of those skipped up to the INDEX keyword, if it is set. If this value is zero, zero briefs will be returned. If the value is greater than the number of available briefs, then this value is ignored and the number of available briefs (COUNT) is returned.

Note: When populating a user interface, it is useful to set this keyword equal to the number of rows in the table.

INDEX

Set this keyword to the zero-based number of the first coverage offering brief to return, skipping over all preceding briefs. If this keyword is not set, all briefs will be returned. You can use this property to enable navigation through a list of briefs displayed in a user interface. For example, suppose there are 10 rows in a table. On the first call to GetCoverageOfferingBriefs, set this value to 0. To display the next set of values, you would set this keyword to 10 (skip the first 10 values and display the next ten.

Examples

The following code parses the URL of a ICEDS WCS server, queries its capabilities (using GetCapabilities) and then extracts information from the returned XML file using GetCoverageOfferingBriefs and GetServiceSection. Information is printed to the Output log.

Note: You may need to replace the URL in the following example as there is no guarantee that the given OCG server will be available when you attempt to establish the connection.

FUNCTION ogcwcs_callback, StatusInfo, CallbackData

PRINT, StatusInfo

; Indicate all is well.

vCancelFlag = 1

RETURN, vCancelFlag

END

PRO ogc_wcs_getcoverbriefs_doc

; Use the GetCoverageOfferingBriefs to access data returned in

; the XML file by the GetCapabilities method.

; This example queries an OGC server at the following URL. Change

; the value of this variable to access a server of your choice.

url="http://data.exelisvis.com:80/cgi-bin" + $

   "/mapserv.exe?MAP=/OGC_Data/WCS/wcs_demo.map" + $

   "&SERVICE=WCS&VERSION=1.0.0&REQUEST=GetCapabilities"

; Catch error.

CATCH, errorStatus

IF (errorStatus NE 0) THEN BEGIN

   CATCH,/CANCEL

   r = DIALOG_MESSAGE(!ERROR_STATE.MSG, TITLE='OGC WCS Error', $

      /ERROR)

   PRINT, !ERROR_STATE.MSG

   IF OBJ_VALID(oWcs) THEN OBJ_DESTROY, oWcs

   RETURN

ENDIF

; Create an IDLnetOGCWCS object and parse a known, working URL to

; set mandatory properties.

oWcs = OBJ_NEW("IDLnetOGCWCS", $

   CALLBACK_FUNCTION="ogcwcs_callback")

oWcs->ParseUrl, url

; Return and parse a brief description of all data holdings on

; the WCS server.

count = oWCS->GetCapabilities()

; Make sure the server returned some coverage offering briefs.

If (count NE 0) THEN BEGIN

; Use the GetCoverageOfferingBriefs method to translate the

; parsed XML data into an array of IDL structures. The NAME

; field of this structure is used to identify what coverage to

; get more information about using the DescribeCoverage method.

briefStruct = oWCS->GetCoverageOfferingBriefs $

(COUNT=briefcount, NUMBER=5, INDEX = 1)

PRINT, "Returning structures for ", + briefcount, + " briefs"

; Access elements of the GetCoverageOfferingBriefs structure.

FOR x=0, briefCount-1 DO BEGIN

PRINT, 'CoverageOfferingBrief = ', strtrim(x,2)

PRINT, ' name = ', briefStruct[x].name

PRINT, ' label = ', briefStruct[x].label

PRINT, ' srs name = ', briefStruct[x].srs_name

PRINT, ' pos1 = ', briefStruct[x].pos1

PRINT, ' pos2 = ', briefStruct[x].pos2

ENDFOR

; Use the GetServiceSection method to get the Service section

; data from the XML file containing the coverage offering

; briefs.

serviceStruct = oWCS->GetServiceSection()

PRINT, 'Service Section'

PRINT, ' name = ', serviceStruct.name

PRINT, ' label = ', serviceStruct.label

PRINT, ' fees = ', serviceStruct.fees

HELP, serviceStruct.keywords

PRINT, ' keywords = ', serviceStruct.keywords

PRINT, ' accessConstraints = ', serviceStruct.access

ENDIF ELSE BEGIN

void = DIALOG_MESSAGE("No information available " $

+ "from WCS Server", /ERROR)

RETURN

ENDELSE

; Cleanup.

OBJ_DESTROY, oWcs

END

Version History

See Also

IDLnetOGCWCS::GetCapabilities, IDLnetOGCWCS::GetServiceSection