Geodatabases, Attributes, and Domains

Introduction:

A geodatabase is a collection of geographically interrelated datasets. For this assignment the Geography 336 class at UW-Eau Claire was asked to develop a personal geodatabase, with a new feature class within it. This newly developed feature class would later be deployed for a microclimate study that would take place the following week. However, in order to properly collect field data, attributes and further, domains need to be determined. By setting domains, the user is establishing rules or limits for the data that can be collected. Thus, domains provide the ability to further specify and record the data captured.

Study Area:

For additional preparation in next week's microclimate survey, the students went out in groups of two on UW-Eau Claire's lower campus to collect data points on a Trimbe: Juno GPS unit. This was essentially a trial run of how to use the device and what to expect of next week. Figure 4.1 is then a view of lower campus with the extent of the trial data collected outlined in black.

Figure 4.1: Study area, located on the lower half of UW-Eau Claire's campus.

Methods:

Again, the first part of this assignment was to develop a new feature class within a personal geodatabase and then create and assign domains to the desired attributes. To conduct this process ArcCatalog was used to organize and design the described geodatabase.

The first step within part one was to create a new work space or folder in which the geodatabase can be created in. Once the geodatabase was created and named, a point geometry feature class was created inside a newly made feature dataset. Inside of this feature class, five separate attributes were created, they were;

• Temperature (Fahrenheit)
• Dew point (Fahrenheit)
• Wind speed (miles per hour)
• Wind direction (expressed as a degree)
• Relative Humidity (percentage)  
• Group number

At this point in time, domains were created in order to specify boundaries or ranges for the attributing data of each point was to be collected. Figure 4.2 is a data table with the different domain fields that were made. For each domain that was created, a brief description, field type and domain type were chosen. Although there are multiple field types that can be specified within a domain's properties, only three were used. Listed below are these field types and their acceptable domain types.

• Text  -  Coded text
• Float  -  A specified range of numbers
• Short Interger  -  A specified range of numbers, or coded text

Figure 4.2: Data table of the domains created for microclimate feature class

Once the domains were decided, they were assigned to the correct attributes to create the parameters needed for the future survey.

The second part of this assignment was to learn how to operate a Juno GPS unit. Again, the purpose of this portion of the lab was to become familiarized with the equipment so that the class could use it in nest week's assignment. To do so, each student went out and gathered a few points and added attributing data onto the device.

Discussion:

At first, creating domains was a bit challenging to do because of the array of field types and ranges that can be applied to it. Understanding which type works best for the desired task, took a little background knowledge to assign them correctly. Thus having a set out plan or design for the geodatabase is important to have prior to the development of it. That way, applying the correct domains and field types can be better accomplished. Other than this, creating the geodatabase, domains and attributes was relatively straight forward to do. If questions did arise, ArcHelp was extremely useful to help clarify them.

Conclusion:

In conclusion, the development of domains, remain very important when collecting attributing data.

By implementing them, guidelines are put in place that can help organize, classify and direct data in a easy to use manner. The creation of this geodatabase then creates a geographic environment in which future microclimate data can be stored.