Those that upgrade to MAP3D 2009 will now be able to use an expression in a friendlier environment thanks to the new expression builder. Anyone that tried to create a complex label for a feature data set knows how hard it was to do in the 2007 or 2008 versions. You were limited to just a few options and you need to make sure the syntax was just right , even when the validate tool reported an error there may not of been an error.
First off depending on what the expression is for as to what the dialog will display. You can use the create/modify expression not only to create a label but also to create a filter to query your data.
The expression dialog to create a label.
The expression dialog to filter your data.
Although the two dialogs look the same at first there are a few extra tools in the filter dialog. The three “Getting Started with……”controls in both dialogs are useful for those that are just starting out creating expressions and will insert the correct code or syntax for those, for the advance users you can turn them off or just start entering your expression by clicking in the dialog box and typing away. So what options or tools are available now, lets take a look. The screen shots below are from a SDF connection so the property menu will vary of you data.
So there you can see there’s a lot of tools to let you create an expression that you can now use, from converting a number value to a text to rounding the number and even doing a mathematical operation like add one value to another and drop the precision of the sum to 2 decimal places all in one expression. The validate option will not only tell you if an error is present in the expression but also moves your cursor to the error in the expression allowing you to edit with out trying to figure out the error message.
Another nice feature it the ability to save the expression to be used again.
The save option creates a xml format file with the extension of fdg. The saved expression then can be loaded and used again with your data at another time.
So there you are a look at the new expression builder in AutoCAD MAP 3D 2009. As time goes on I’ll post a few tips on how to use it.