When in Doubt, Steal It
This is a provocative title, to be sure, especially with all the news of late about spying and identity theft. When it comes to setting up standards, however, whether they be typical CAD standards or GIS, sometimes “stealing” other people’s standards can be crucial. It’s also completely legal.
Setting up a new GIS system or adding new data to an existing one can be daunting at times. Where does one begin? As most everyone who has worked with GIS knows, adding data can be intimidating and often tedious.
Luckily for MAP users, borrowing standards from others is easy. There are a few steps to start, but once competed, they can be used over and over again.
Step 1: Bring in Existing Data
The first step is to bring in the data you want to copy from. In my examples, I’m using property data developed by the City of Bismarck, North Dakota. Use Map Import and be sure to import not only the entities, but all the data as well. To do this, click on the Data cell and toggle “Create Object Data” (see Figure 1). You can also click on “Select Fields” and specify what data to bring in, because there may be times when you want to add only some of the data to your new standards.
Figure 1: Importing data
You can also import one set of data or multiple as shown in the figure above. It all depends on what you want to accomplish, such as creating new standards for one or more entity types.
Step 2: Create Object Classes
This is where we create an object class for—in this case—property data. An object class is nothing more than an XML file. Before you begin, however, you need to have administrative privileges. To do so, MAP has created Superuser (not case-sensitive) with the password SUPERUSER (case-sensitive). You can either keep that login or create a new one. Just make sure you give the new user superuser privileges. To login simply click on the Map Setup tab on the ribbon and click “Map” on the far left. From there simply click on User Login. Make sure, too, you have the Task Pane open (MAPWSPACE: 1).
Once you’re logged in, click on the Map Explorer tab on the Task pane. Right-click on “Object Classes” and “New Definition File.” It will automatically take you to the folder in which your current drawing is saved, and you name the file however you want. Click “Save” and you’re ready to go. You’ll notice that nothing has changed in the Task pane, but that’s okay. Once you create the definition file, Map automatically loads it.
Next we need to create an object class. In this example, I want to create a parcel data object class that contains a parcel number and land use.
First, pick the entity from which you want to copy, right-click on “Object Classes” and click on “Define Object Class.” The first tab shows the type of entity it is (see Figure 2a). In this case it’s a polyline. Checking it limits the application to that object class to polylines only. That could come in handy if your drawing contains points and text and you don’t have to worry about accidentally selecting one of those when applying the class to new entities.
Figure 2a: Define object class
Next click on the Properties List tab (see Figure 2b). Here you can check the properties you want to include in your new data as well as add a range (for example on a waterline, you can limit it to 4”-24” for size and PVC, DI for type). You can also add new properties to the class if need be. Simply click on “New Property” and give it a new category heading and name as well as data type such as text, integer or real values.
Figure 2b: Properties List tab
Pay particular attention to the Default under Property Attributes. When you picked the entity on which to base the object class, Map assumes that the data of that object is the default. You may not want that, so I would leave the Default property blank. Otherwise when you classify new objects, each one will have the same data attached to it. Not a huge deal since you’ll have to add the new data either way, but at least if it’s blank, you’ll know that it hasn’t yet been edited to include the proper data.
Once you’ve modified, included, and added all the properties you need, simply click “Save Definition.”
You should now see your new definition appear below “Object Classes” (see Figure 2c).
Figure 2c: New definitions
Step 3: The Fun Part
Now that you’ve created your new definition file and object classes, it’s time to put them to use. In this example, I’m using the City of Mandan’s city map which is a basic CAD drawing. I want to create a system similar to Bismarck to the Mandan drawing.
Once you open the drawing (if you exited out of AutoCAD, you will need to login again). Go to Map Explorer on the Task pane and right-click on “Object Classes.” Next click on “Attach Definition File” and choose the file you want.
We next want to classify specific objects. In this example I want to start with the subdivisions. Luckily, they are all on a Subdivision layer, so I isolate it. I then right-click on the appropriate definition—in this case Subdivisions—and choose “Classify Objects.” (Note: all of these commands are available on the Create tab on the toolbar in the Drawing Object section.) A dialog pops up asking if you want to include and/or exclude certain objects (see Figure 3a).
Figure 3a: Classify Objects dialog box
These options can be quite handy, as was mentioned earlier in the discussion about excluding text or points and excluding objects that have been previously classed so you don’t accidentally override existing data. Once I check/uncheck what I need, I’m asked to select the objects I want to classify. In this example, I choose everything on the Subdivision layer.
Figure 3b shows the data now attached to the subdivision boundary. Notice that there is some data that will need to be modified such as the township, acreage, and year. This is why it’s important to double-check the defaults when creating the definition file. Nevertheless, it is now easy to make the appropriate changes to all the polylines.
Figure 3b: The results
Once all the data is added, I can now export out as shape files or other GIS formats to share with others. Another good use of definition files is you can now share the data with the company from which who you “stole” the standards and they don’t have to make any changes on their end to make the new data fit in their system. The definition files also prevent extraneous and incompatible data from entering other systems.
