In the last skill, you saw how to make use of point data in a Microsoft Access database. However, you may also receive point data as plain ASCII text files in which the items of data are separated by spaces or commas. Also, if you are working on a project with colleagues who use AutoCAD Civil 3D, you may receive point data in the form of LandXML files.
ASCII files are simple and convenient but they can only store one type of points or one point group. The advantage of using LandXML files is that they can store multiple point groups. A point group is a way to categorize points according to their function and purpose. For example, the illustration below shows part of a site plan in AutoCAD Civil 3D. There are four point groups in this drawing:
AutoCAD Civil 3D has sophisticated features for handling and displaying points. For example, in this illustration, each item of attribute data, such as the description and the elevation, is styled individually. The illustration on the left below shows how these point groups appear when they are imported into AutoCAD Map 3D. The point groups appear with the default symbol for survey points and the default attributes, which are the first two columns in the data table.
The illustration on the right shows the point groups after they have been themed in Display Manager using the Code attribute (for example Code = POND) to distinguish between the point groups. Symbols (blocks) have been assigned to each point group. The label for each point group has also been modified to show only the point ID.
The first demonstration shows how to use the Survey tab in AutoCAD Map 3D to import and manage point groups. In this example, the points are imported from a LandXML file. However, the procedure is essentially the same when you import ASCII files.