IDRISI vector format in .vct files. VCT files may automatically provide coordinate system information. VCT files are often accompanied by .vdc files that provide documentation. VDC files are plain text files that may be opened with Notepad. Such files can be useful for the detective work involved in figuring out what coordinate system a VCT file is supposed to use, if the coordinate system is not automatically specified.
To import from VCT format:
Choose File-Import from the main menu.
In the Import dialog browse to the folder containing data of interest.
Double-click the file ending in .vct for the data of interest.
A table, drawing, and possibly comments will be created.
We can double-click on drawings that are created to view them. For a more interesting display, we first create a new data source using a Bing street maps image server as shown in the Example: An Imageserver Tutorial topic. We then create a map and drag and drop the Bing layer into the map, and then we drag and drop a drawing into the map.
In the above, we have dropped a drawing into the map. It appears using the correct projection, using default formatting.
We zoom in and use the Style pane to color the areas, and the Layers pane to apply some transparency, which allows us to see the drawing closely aligns to the Bing map. We see the drawing shows the approximate coverage of zip codes in Massachusetts.
As discussed in the ZIP Codes are Not Areas essay, Zip codes in the US do not identify areas but instead identify linear, point, or abstract, location-less destinations. People using Zip codes as areas more likely are using ZCTAs, that is, Zip Code Tabulation Areas, which are approximations created by the Census Bureau.
Projects and .map Files
ZIP Codes are Not Areas