= grate inlet
104 = junction box
106 = Y inlet
107 = junction box/manhole
108 = outfall
109 = headwall
110 = beehive inlet
111 = manhole
The type of data collected for these features includes a description, flowline elevation, inlet size, top elevation, year built, designation for a public or private line, and a rotation angle.
Analyze the descriptions of this data and determine what feature datasets and feature classes need to be created, what fields they should contain, any domains that might need to be created, and any subtypes that might be beneficial.
•Print a set of the geodatabase design forms as necessary.
•Use the forms to create the logical model of feature classes for the zoning polygons and zoning boundaries.
•Investigate the use of domains and subtypes to build data integrity and behavior into your design.
Getting started
Here’s a little help to get started:
•Decide how many feature classes you want to create.
•List the fields that will need to be in each feature class.
•Determine the field type, null status, and default value for each field.
•Investigate the use of domains for these fields.
•Look for fields that describe a “type” or “category” that could be used as a subtype, such as fixture type.
WHAT TO TURN IN
If you are working in a classroom setting with an instructor, you may be required to submit the design forms you created in tutorial 1-2.
•The completed design worksheets for:
Review
Whereas the first tutorial focused on the development of a geodatabase to contain parcel-related information, this tutorial focused on the development of a geodatabase to represent a sewer system. Both tutorials focus on real-world examples of the types of critical information managed by every city, town, or other local governmental entity. Given the tremendous municipal resources dedicated to the management of these systems, an adequate foundation for managing them is essential. The geodatabase allows for physical information, as well as information on the behaviors among the components of these systems, to be accurately portrayed in a GIS. By using the combination of good information and good data integrity controls (behavior), the geodatabase enhances effective and efficient decision-making capabilities.
One of the most critical steps in developing a comprehensive geodatabase is the initial planning phase. Although we have focused on and discussed GIS functionality within both tutorials, we have yet to even start a create process in the software! Planning for a geodatabase development project involves both gathering the physical system requirements and understanding how interrelated objects behave in the physical system. To further enhance your design, you will also need to know what kinds of questions your customers will need to have answered. Once an adequate knowledge of the system is gained, it is then up to the skill of the geodatabase developer to build these capabilities into the corresponding geodatabase.
A properly designed geodatabase will be worthless to the engineers and others who rely on it to represent the real world if it is full of errors. The geodatabase allows the designer to apply domains to feature attributes to ensure that the correct information is correctly recorded within the geodatabase. Flexibility to adequately portray and control features and their behavioral characteristics within the model is afforded using subtypes of features. Interrelated behavior among features is enhanced using topology. The success of a geodatabase often depends on a thorough knowledge of how and when to apply these data integrity tools.
STUDY QUESTIONS
1.What is topology, and why is it an important concept when designing a logical model of a geodatabase?
2.Think about the principal ways in which features are represented spatially within GIS. Give an example of each feature type, a possible domain for each type, and possible subtypes for each type. Explain your rationale.
3.Why is it important to fully understand a system to be represented and managed in GIS? How do you determine its structure?
Other study topics
Search for these key phrases in ArcGIS Pro Help for further reading:
1.Introduction to subtypes
2.Geoprocessing considerations for attribute domains
3.Geoprocessing considerations for subtypes
Chapter 2
Creating a geodatabase
Chapter 1 covered many aspects of designing a geodatabase, and now it’s time to build one. A slow, methodical approach is best, making sure that each detail of your planned design is implemented exactly. In this chapter, you will create geodatabases, feature datasets, and feature classes—and apply all the domains and subtypes that were introduced in chapter 1. Then at the end of this chapter, you will get a chance to create and edit some data within this new structure and see how a good design makes data creation and management easier.
Tutorial 2-1: Building a geodatabase
Designing a geodatabase can be a long and drawn-out process, but it’s only after that phase is completed that the data structure can be created in ArcGIS Pro. A good design will greatly simplify the creation phase and make it go smoother and faster.
LEARNING OBJECTIVES
•Work with ArcGIS Pro
•Create a geodatabase
•Build a database schema
Introduction
A good database design is essential for the smooth creation of a geodatabase. It is best to think through the entire design, documenting your needs and addressing them with the logical model. Once that is completed, the creation phase can begin.
Databases can be sensitive to change, and in fact, some elements, once created, cannot be changed. They can only be deleted, and then re-created. It is therefore important when using the creation tools to pay attention to what has been designed. Creating a feature class without regard to the data type will result in wasted time because the data type cannot be altered later. The same holds true for field names and null
