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Using VRT Files to Import ODBC, CSV

Using VRT Files to Import ODBC, CSV. Problem : Many data sources come in comma delimited or in Excel or database formats Solution : VRT files describe the data source so they can be easily imported into Bentley Map Notes: Works best with point features

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Using VRT Files to Import ODBC, CSV

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  1. Using VRT Files to Import ODBC, CSV • Problem: Many data sources come in comma delimited or in Excel or database formats • Solution: VRT files describe the data source so they can be easily imported into Bentley Map • Notes: • Works best with point features • Capitalization is important in the various parameters

  2. What is VRT (Virtual Datasource) • An XML format file that describes the format of the source data • Data source • Feature name • Spatial Reference System • Field encoding Sample VRT <OGRVRTDataSource>     <OGRVRTLayer name="SurveyMon">         <SrcDataSource>SurveyMon.csv</SrcDataSource>         <GeometryType>wkbPoint</GeometryType>         <LayerSRS></LayerSRS>         <GeometryField encoding="PointFromColumns" x="Easting" y="Northing"/>     </OGRVRTLayer> </OGRVRTDataSource>

  3. Common Parts of VRT file Name of feature <OGRVRTDataSource>     <OGRVRTLayer name="SurveyMon">         <SrcDataSource>SurveyMon.csv</SrcDataSource>         <GeometryType>wkbPoint</GeometryType>         <LayerSRS></LayerSRS>         <GeometryField encoding="PointFromColumns" x="Easting" y="Northing"/>     </OGRVRTLayer> </OGRVRTDataSource>

  4. Common Parts of VRT file <OGRVRTDataSource>     <OGRVRTLayer name="SurveyMon">         <SrcDataSource>SurveyMon.csv</SrcDataSource>         <GeometryType>wkbPoint</GeometryType>         <LayerSRS></LayerSRS>         <GeometryField encoding="PointFromColumns" x="Easting" y="Northing"/>     </OGRVRTLayer> </OGRVRTDataSource> Source for feature

  5. Common Parts of VRT file <OGRVRTDataSource>     <OGRVRTLayer name="SurveyMon">         <SrcDataSource>SurveyMon.csv</SrcDataSource>         <GeometryType>wkbPoint</GeometryType>         <LayerSRS></LayerSRS>         <GeometryField encoding="PointFromColumns" x="Easting" y="Northing"/>     </OGRVRTLayer> </OGRVRTDataSource> Feature Type

  6. Common Parts of VRT file <OGRVRTDataSource>     <OGRVRTLayer name="SurveyMon">         <SrcDataSource>SurveyMon.csv</SrcDataSource>         <GeometryType>wkbPoint</GeometryType>         <LayerSRS></LayerSRS>         <GeometryField encoding="PointFromColumns" x="Easting" y="Northing"/>     </OGRVRTLayer> </OGRVRTDataSource> Spatial Reference

  7. Common Parts of VRT file <OGRVRTDataSource>     <OGRVRTLayer name="SurveyMon">         <SrcDataSource>SurveyMon.csv</SrcDataSource>         <GeometryType>wkbPoint</GeometryType>         <LayerSRS></LayerSRS>         <GeometryField encoding="PointFromColumns" x="Easting" y="Northing"/>     </OGRVRTLayer> </OGRVRTDataSource> Encoding (Column names containing XY(Z) values)

  8. CSV Example Source Data: SurveyMon.csv Easting,Northing,ID,Elevation 602639.5381,4049623.398,1,282.9576447 669949.1987,4061243.25,2,282.3723275 617433.4852,4004901.709,3,265.455676 640922.0652,4096213.903,4,228.7933358 680351.1314,4008944.322,5,211.2217422 689200.8667,4010622.815,6,278.4353313 600382.0976,4086158.497,7,203.1683236 630393.1237,4095834.27,8,262.3779305 644160.8595,4016882.563,9,261.6596222 660532.9288,4092362.074,10,243.4360725 VRT File <OGRVRTDataSource>     <OGRVRTLayer name="SurveyMon">         <SrcDataSource>SurveyMon.csv</SrcDataSource>         <GeometryType>wkbPoint</GeometryType>         <LayerSRS></LayerSRS>         <GeometryField encoding="PointFromColumns" x="Easting" y="Northing"/>     </OGRVRTLayer> </OGRVRTDataSource>

  9. The Map Interoperability Tool • File -> Map Interoperability • Import -> New Import • Add file… • Set All File Types • Show Properties -> Ungrouped

  10. Import the Data • All headings from CSV are present, including system generated FID • Set any WHERE clauses or spatial constraints • Set any required symbology • Import the data

  11. Review the Imported Features • Feature named correctly • <OGRVRTLayer name="SurveyMon"> • Located at correct location • <GeometryField encoding="PointFromColumns" x="Easting" y="Northing"/> • All other properties imported

  12. A Note About Coordinate Systems • <LayerSRS></LayerSRS> specifies the geographic coordinate system (GCS) of the input data • Examples are: • <LayerSRS>WGS84</LayerSRS> • <LayerSRS>GEOGCS [ "GDA94", DATUM ["Geocentric Datum of Australia 1994 (EPSG ID 6283)", SPHEROID ["GRS 1980 (EPSG ID 7019)", 6378137.0, 298.257222101]], PRIMEM [ "Greenwich", 0.000000 ], UNIT ["Decimal Degree",0.0174532925199433]]</LayerSRS>

  13. A Note About Coordinate Systems • Because the GCS can be difficult to define, a simple workaround is to omit the GCS definition and import to a DGN to which the GCS of the data has been assigned. • Reference to other DGN files or reassign GCS • Sample data is MTM27-10 • Import to DGN file with GCS defined as: • Reassign GCS as required for transformation

  14. Database and Spreadsheet Sources • Require an ODBC connection to be setup which is specified in the data source parameter • SrcDataSource>ODBC:SurveyMonXLS</SrcDataSource> • Because there can be multiple tables or sheets in each source, an additional parameter is required • <SrcLayer>MonumentData</SrcLayer> • This defines the table or range name in the source • All other parameters remain the same

  15. ODBC Example – Excel Spreadsheet • Setup ODBC link to XLS file • File must be in Excel 97 – 2003 format • Data is as shown • Range Name (MonumentData) defines the extent of the cells to import including the column headers

  16. ODBC Example – Excel Spreadsheet VRT File <OGRVRTDataSource>     <OGRVRTLayer name="SurveyMon">         <SrcDataSource>ODBC:SurveyMonXLS</SrcDataSource> <SrcLayer>MonumentData</SrcLayer>         <GeometryType>wkbPoint</GeometryType>         <LayerSRS></LayerSRS>         <GeometryField encoding="PointFromColumns" x="Easting" y="Northing"/>     </OGRVRTLayer> </OGRVRTDataSource>

  17. ODBC Example – Access Database • Setup ODBC link to MDB or ACCDB file • Data table is as shown • Source layer is the name of the table

  18. ODBC Example – Access Database VRT File <OGRVRTDataSource>     <OGRVRTLayer name="SurveyMon">         <SrcDataSource>ODBC:SurveyMonMDB</SrcDataSource> <SrcLayer>SurveyMon</SrcLayer>         <GeometryType>wkbPoint</GeometryType>         <LayerSRS></LayerSRS>         <GeometryField encoding="PointFromColumns" x="Easting" y="Northing"/>     </OGRVRTLayer> </OGRVRTDataSource>

  19. Linear and Polygon Sources • Require a custom format for the data • Geometry type is • <GeometryType>wkbLineString</GeometryType> • <GeometryType>wkbPolygon</GeometryType> • For more information and examples: http://communities.bentley.com/products/geospatial/desktop/f/5924/t/65028.aspx

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