| Step 3: Create Feature Classes |
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The feature class is a storage location for coordinates and attributes of a feature.We will create feature classes for light pole, sidewalk and parking lot locations. At the end of this step, you will create additional feature classes for buildings, trees and other features of your choosing.
1. To create a new feature class for light pole point features Note, it is not required that feature classes be placed within a feature dataset. They can exist in the geodatabase at the same level as the feature dataset but they will not be able to participate in relationships with other feature classes. We will place all our training feature classes in the feature dataset created in the previous step. Right-click on the GPS_Features feature dataset Choose New / Feature Class The Feature Class dialog box opens Enter the feature class name, Light_Pole Enter an Alias if you wish to do so. Tip An alias, unlike the field name, does not have to adhere to the limitations of the database, so they can contain special characters such as spaces. By specifying an alias, you can use a more "user friendly" description of the content of the field than their actual field name. From the drop-down menu, choose Point Features for the Feature Type Check the boxes to include Z and M values as you wish Click Next to continue 2. To view the attribute fields for this new feature class Click on SHAPE in the Field Name column Note the Geometry Type is Point as indicated in the Field Properties at the bottom of the window. 3. To create more attribute fields to store additional information about the light poles In addition to its location, ArcPad allows you to record information, or attributes, for each of these features. We will record the light pole height and the other 5 attributes as shown.
Click on the blank line below SHAPE in the Field Name column Enter Height_Feet Field names must start with a letter and not contain spaces or reserved words. Field names are limited to 31 characters. Field names in the same table must also be unique; for instance, you can't have two columns with the name Height_Feet. TIP Include desired units within the attribute field name, to prompt the user how to answer the question. Press the Tab key to advance to the Data Type column From the drop down list, choose the data type of Short Integer To review the various data types, refer to the section describing the components of a GDB on this site.
In the Field Properties at the bottom of the window Enter an Alias if you wish. If Allow NULL values is Yes, the user is not required to provide an attribute value for this attribute while collecting the feature. If a value is required, change Allow NULL values to No Default Value is optional, leave it blank for now
4. ON YOUR OWN As you did for Height_Feet, add these fields with the corresponding data types. As you enter each field, examine the Field Properties at the bottom of the window and notice how they differ for each Data Type. Field Name Data Type Wattage Short Integer Pole_Material Text Condition Text GPS_Date Date Comment Text Note: What happens if you try to enter Date or Text as a field name? Why do you think this happens? ____________________________________________________ ____________________________________________________ The completed window should look like this -
Click Finish to save your work and close the Feature Class Properties window 5. To view the results of your efforts In ArcCatalog, view the point feature class button and its hierarchy within the geodatabase 6. To view the feature dataset properties Right-click the Light_Pole feature class and choose Properties Review the attributes and corresponding data types in the Fields tab 7. To view the attribute table for the Light_Pole feature class In the ArcCatalog tree, select the Light Pole feature class In the right panel, choose the Preview tab at the top of the window From the Preview drop-down menu at the bottom, choose table
The field names you entered are the table column headings. The starred (*) fields were automatically generated by ArcGIS. These are essential to how ArcGIS storages each record. They should not be edited in the field using ArcPad or within ArcGIS. While the table schema is established, there are still no actual features to view since we have not collected any data.
8. ON YOUR OWN i. Design your own Point feature class representative of a point feature you commonly encounter in the field. Be sure to include attributes for a short integer data type, a text data type, GPS_Date and a Comment to serve as a backdoor.
ii. Create the above Your_Point feature class in the same feature dataset as you did for light poles iii. Create a Sidewalk feature class as shown below in the same GPS_Features feature dataset. Be sure to specify the Geometry Type of Line
You have now created the Light_Pole and Sidewalk feature classes as well as the Your_Point feature class of your own design. In the next step, you will create a feature class and the attribute fields for Parking Lot. Since Parking Lot shares nearly identical attributes with the Sidewalk feature class, we will discuss a great tip for working efficiently! 9. To create a Parking_Lot feature class of the Geometry Type Polygon Create the feature class Enter an Alias and specify Z and M Values as you wish Click Next 10. To import attribute fields from the Sidewalk feature class to the Parking_Lot feature class We are to record the 4 of the same attributes for parking lots as we did for sidewalks.
With the exception of Width_Feet, which does not apply to a polygon feature, we are to collect all the same information as we did for the Sidewalk feature class. While you could manually enter all the same fields for parking lot, the Import button offers a faster alternative. In the New Feature Class window, click the Import button
Navigate to the Sidewalk feature class and click Add The Parking_Lot feature class fields have now been populated with the fields from the Sidewalk feature class.
11. To delete the unneeded Width_Feet attribute Since Width_Feet attribute from the Sidewalk feature class is not needed for the Parking_Lot feature class, it should be deleted. Click on the left-most, column for Width_Feet and press the Delete key on the keyboard
TIP Fields can be imported from feature classes from any geodatabase or table. Other ideas for working more efficiently are to copy and paste feature classes, feature datasets or entire geodatabases for incorporation into your own GDB. 12. ON YOUR OWN i. Design your own Line and Polygon feature classes representative of a line and polygon features you commonly encounter in the field. Be sure to include attributes for GPS_Date and a Comment attribute fields to serve as backdoors.
ii. Create ‘backdoor feature classes for Generic_ Point, Generic_ Line, and Generic_ Polygon. These require only a Comment attribute field as shown below -
You have now created the all the needed feature classes and their attributes.In the next step, you will create range and coded values domains.
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