GetBlob Method
Description
Gets a Blob string of the current open Item within a Coordinate Reference System
Syntax
Visual Basic |
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Public Function GetBlob( _ ByVal projection As String, _ ByVal fmt As Integer, _ ByVal precision As Integer _ ) As String |
Parameters
- projection
- The named Coordinate Reference System of the returned Blob string. This can be defined as:
- OGC URNs (eg 'urn:ogc:def:crs:OGC:1.3:CRS84')
- EPSG URNs (eg 'urn:ogc:def:crs:EPSG::27700')
- EPSG code strings (eg 'EPSG:27700')
- EPSG URLs (eg 'http://www.example.com/epsg#27700' or 'http://www.example.com/epsg.xml#27700')
- EPSG codes as a simple string (eg '27700')
- fmt
- The format of the stored Item Blob.
SIS_BLOB_OGIS_WKT 2 = OGC Well-Known-Text format SIS_BLOB_OGIS_GML 3 = OGC Geographic Markup Language SIS_BLOB_GEOJSON 6 = Geographic Objects for JSON format - precision
- This parameter is ignored and will always return 64-bit precision.
If blank, this will default to the CRS of the current Item’s Dataset.
Return Type
A string describing the current open Item in the chosen format. SIS format strings are encoded and can only be interpreted by SIS.
Remarks
There is no limit on the length of Blob strings generated by SIS.
There are however limits elsewhere: GisLink can only handle strings of a few Kb (this does not apply to the SIS Control); SIS datasets which read Blobs from data sources can use a fixed size communication buffer (use the Cadcorp OGC SQL92 Database Maximum Blob size, and Cadcorp View Geometry Maximum Blob size properties to change the size of the communication buffer).
Available: GEO OD SISpy
Groups:
Example
sis.GetBlob ( "*APrjNatGrid", 0, 0 )
Returns the Blob string of the current item within the National Grid coordinate reference system.