Creates an Item from a Blob string. If a Group is open, then graphics are added to the Group, otherwise a new Item is created.
| Visual Basic |
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Public Function CreateItem( _ ByVal blob As String, _ ByVal prj As String, _ ByVal fmt As Integer _ ) As Integer |
The format of the stored Item Blob.
| SIS_BLOB_SIS_V6_ASCII | 0 = Cadcorp SIS format |
| 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 |
When modifying an item which is stored as a blob in a database, it is good practice to create a temporary version of the item on an editable overlay, and only commit the changes to the database, having got the new Blob string using GetBlob, when the user is satisfied with the changes. This allows any changes to other columns in the database table to be done in the same transaction.
Open Geospatial Consortium WKT format enables the creation of items directly as an alternative to the MoveTo/LineTo and StoreAsLine/StoreAsArea methods. Below are examples of the WKT syntax for creating various geometry items. The StoreAsArea method is unnecessary after creating an area using this method.
To create a polygon item, an L shape 30 metres by 30 metres:
sBlobText = "POLYGON ((0 0,30 0,30 10,10 10,10 30,0 30,0 0))"
GisCreateItem (sBlobText, "*APrjNatGrid", SIS_BLOB_OGIS_WKT)
To create a polygon item 30 metre square with 10 metre square hole:
sBlobText = "POLYGON ((0 0,30 0,30 30,0 30,0 0),(20 20,20 10,10 10,10 20,20 20))"
GisCreateItem (sBlobText, "*APrjNatGrid", SIS_BLOB_OGIS_WKT)
X and Y coordinates are separated by a space, and each pair of coordinates is separated by a comma. Use the GetBlob method to analyse the syntax of other geometry types.
Available: GEO MM ME MD OM OD OV SISpy
Group:
sis.CreateItem (blob, "*APrjNatGrid", SIS_BLOB_SIS)
Creates an item on the current overlay using the value of blob.
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