AutoCAD Map 3D, which is sold as a stand-alone application, but is also included with Land Desktop and Civil 3D, allows you to use queries. Using queries, you can search through one or many drawings and identify, select, isolate, modify and/or copy drawing objects and extract information that would otherwise be extremely tedious and difficult to do by hand. The word “query” is one of those curious sounding terms we associate with database management systems, GIS and other highly specialized software. All it really means is ask a question.
With queries, you specify a set of criteria to identify and select objects, and then place those objects into another drawing. You can also modify them or create reports detailing the information found. There are four types of criteria you can define in a query: location, property, data, and SQL. You can also use combinations of different query types to create compound queries. It’s all controlled from the Define Query dialog box, which you get to through the Map Explorer tab of the Task Pane.
Location queries find objects based on their proximity to geometry that you define in the drawing editor, such as circles, polygons, fences and windows. Examples of location queries might include finding all objects within a circle of a given radius. A compound location query might find all objects within a window that also cross a particular boundary line.
Property queries find objects based on AutoCAD properties, such as area, layer, color, linetype, length, elevation, etc. Examples of property queries are finding all objects on a certain layer that are NOT colored by layer, or all spot elevations with a particular Z-coordinate.
Data queries find objects and associated data in any of several forms, including object data and linked external data, (which we explored in January and February), as well as feature classes and attributes. Data queries more closely resemble the kinds of queries you may be familiar with in DBMS software such as Access. Examples of data queries include finding all pipes made of ductile iron and installed before a certain date, or all taxlots larger than one acre and valued under $50,000, (provided of course that this data is attached or linked to the objects).
Examples of compound queries involving more than one query type include finding all taxlots that have residential development within ½ mile of a project site. In addition to identifying them on screen, you could also easily produce and export a report of the names and mailing addresses and use it for a mail-merge.
Any of these queries, simple or compound, can also be used to modify objects, using the Alter Properties feature. Once objects are found and selected, their properties, such as layer, color, elevation, rotation, text style or value, and/or scale can be instantly and automatically changed. Think of all the times you’ve encountered a drawing where some of the entities are on the wrong layers, or not colored by layer – one easily defined query would not only find them all, but instantly fix them, too.
Once you start to think about all the times you’ve had to manually crawl through a drawing, layer by layer, selecting objects and revealing the properties values, you can begin to appreciate how many hours of tedium this feature alone could save you. There is virtually no limit to the number of ways you could combine the various query types to instantly select objects in any imaginable way.
Creating queries is one of many skills you will learn in our books “Digging Into Autodesk Map 3D”. We offer editions compatible with versions back to 2004.