readme.txt

MO VB地理信息系统程序设计

This sample demonstrates the use of the projection objects ProjCoordSys and GeoCoordSys, and the CoordinateSystem property of the MapLayer object and Map control. The Export method of the Recordset object is used to export projected data, and the FindCoordinateSystem and FindArcInfoCoordinateSystem methods of the DataConnection object is used to read projection metadata.
To use the sample, first load a map layer by pressing the AddLayer button. Navigate to a directory with shapefiles or ARC/INFO coverages and select a file. If the projection metadata file was found for that GeoDataset (a .prj file), then the CoordinateSystem property of the MapLayer will be set automatically. 

If no metadata was found, you can set the CoordinateSystem of the MapLayer manually. Click either the 'Projected Coordinate System' or 'Geographic Coordinate System' option, and select a pre-defined coordinate system from the drop-down list on the right. Click 'Set Layer Coordinate System'  to apply the selected option to the MapLayer. Now repeat the process for the Map control, ending by clicking the 'Set Map Coordinate System' button. Now you are viewing your MapLayer projected on-the-fly to the Map control's coordinate system. The data underlying the MapLayer remains unchanged. 

To load a projection metadata file as a custom coordinate system option, click 'Read PRJ File', and select a projection metadata file in the dialog box. The details of the coordinate system are read from the metadata file and a new ProjCoordSys or GeoCoordSys coordinate system object is created. The drop-down list now presents this coordinate system as an option for setting on the Map control or MapLayer, by clicking the 'File Coordinate System' option.  

Clicking the 'Export Layer Projected' button allows you to Export the current MapLayer to a shapefile, transformed to the current coordinate system set on the Map control. Navigate to a suitable directory and give the new shapefile a name, then click Save. 
This sample does not use any particular data sets.