PrintQuality and Quality Management in GIS Projects
Quality Parameters
With the general definition of quality, "the degree to which project deliverables meet requirements", the challenge for GIS projects is to properly define specifications and specific quality parameters that are appropriate for different types of GIS projects and deliverables. In GIS projects, quality can be defined (and ideally measured and assessed) for specific deliverables such as:
- reports and documents (needs assessment, design documents, plans, etc.)
- conceptual and physical database designs
- spatial data collected from aerial surveys and processed for delivery to users (orthoimagery, LiDAR elevation data)
- GIS data compiled from field data collection, map digitizing, or other means
- GIS applications (custom-designed user interface and functionality from GIS software)
Defining quality parameters for GIS project deliverables should be done as part of project planning--to provide a basis for project work and quality assurance activities. Documented specifications for project deliverables establishes the basis for quality management. Table 7-1 below identifies quality criteria associated with different types of GIS project deliverables.
NOTE: Review Table 7-1 closely. For Assignment #6, you will specifically need to address quality parameters for Metropolis deliverables that relate to the last two (right side) columns of this table.
| Project Reports, Documents, MAP Products | Conceptual and physical database designs | Aerial Data Collection | Compiled GIS Data | Custom GIS Applications |
|---|---|---|---|---|
|
|
|
|
|
*includes specified allowable "error of omission" level (required features captured) and "error of commission" (non-required features captured by error). An example of "error of commission" would be a GIS project involving the collection of manhole locations for a wastewater utility network. If the collection included, by error, some gas main manholes as well--there would be commission errors (the gas manholes should not be part of the database).
Quality planning establishes quality parameters and a level of expected quality for those parameters, and it describes the use of necessary tools and procedures to ensure that the level of quality is attained. Quality planning should occur as part of the development of project deliverable specifications and work planning.
As indicated in Table 7-1 above, quality planning for GIS projects may include several important aspects, some of which overlap with those identified for information technology projects, and some of which are unique to GIS. For example, functionality and usability are important aspects of many IT development projects. If you are customizing a user interface for a GIS application, you will need to address these issues of functionality and usability. If, however, you are creating paper copies of maps for botanists to use as they collect samples, functionality and readability relative to how the map will be used is important. The most rigorous and detailed quality planning and quality control procedures are associated with GIS data compilation and processing projects. For GIS data, there are fairly mature, documented standards, and data quality lends itself to a greater level of quantification than quality criteria that are more subjective. Several government and professional organizations have documented standards for spatial data content, format, and overall quality.
In GIS projects, there is considerable focus on quality management for GIS data and custom application development. Read Croswell, subsections 7.4 and 7.5, for an overview of GIS database and application development considerations. Also, take a look at the tutorial document on GIS database QC and QA.
Approaches for Ensuring Quality in GIS Projects
In major GIS database development projects, like the one being launched by the City of Metropolis, it is common practice to prepare an initial database design and set up database development procedures (including QC steps) and then initiate a pilot project--a task or subproject that is part of the overall database development project. The purpose of the pilot is to test the design, source material management, data capture and development procedures, QC approach, etc., and then to use the pilot project results to refine the design and procedures before initiating production work.
In GIS database work, the concept of incremental data improvement is important. Consider a major GIS database project for a water utility organization which has the objective of developing a complete GIS database of the water distribution network with such features as water mains, valves, hydrants, fittings, service lines, etc. The project also captures attribute information about the water facilities like pipe diameter, material, installation date, and others. Even a very well-planned project that uses available sources (as-built engineering drawings, work orders, water service line connection permits), may not result in a fully complete and accurate database (in relation to facilities actually in the field). In this case, a process of "incremental accuracy" may be put in place to improve data quality over time. The water utility organization has people in the field on a continual basis performing inspections and maintenance activity. These individuals observe facility status in the field and, with the right field-based tools deployed with mobile devices, can capture information that will improve GIS data quality over time. Such improvements may include: a) improved positional accuracy based on field-collected coordinates, b) populating attribute data missing from the initial data capture (e.g., correct pipe material), and c) capturing features located in the field (missed in the initial database development). This can be done by deploying field-based GIS applications with a location-aware devices (smartphone, tablet computer) that allow field personnel to capture new data that will drive GIS database improvements.
GIS software provides tools for customizing applications that meet the needs of users. The types of customization work that often come up in GIS application development projects include:
- automating access, integration with other systems or databases, or import/export of files with external databases and applications
- designing and developing “intelligent” interactive forms for attribute or graphic data entry (includes use of dropdown pick lists, automatic error checking, and other controls)
- developing application scripts that can be launched by a simple menu pick and combining a number of individual functions
- designing and creating templates for standard maps and textual reports
- creating data quality control and quality assurance applications using validation tools provided by the software package
- creating a library of standard queries that can be accessed through a menu
- programming complex analysis functions using basic GIS processing command
- building custom geospatial statistics or analysis models (e.g., network analysis)
The types of quality issues that are important in planning and execution for software and GIS application development projects are:
- proper functionality
- usability and adherence to user interface standards
- efficiency, performance, response time
- adherence to coding, programming standards
- flexibility and maintainability
- proper access to GIS data sources
- completeness and clarity of documentation
Software and application development work can follow a number of formal methodologies. The key point is that a formal, organized methodology should be put in place and followed during project execution. As a matter of quality management, key steps in the process (user application needs assessment, design, prototyping, operational deployment, documentation) should have defined steps for user review and comment which is used by the development team to incrementally refine the applications in a process that culminates in deployed applications that meet stated requirements.
For Assignment #6, you will work as a team to prepare a quality management plan for the City of Metropolis Geodatabase Development Project. The basis for this plan is the description of deliverables required by the City and, for GIS data deliverables, the specific quality criteria and levels defined in the RFP (Section 5).