Introduction
The Urban Atlas of the Phoenix Metropolitan area took three years to complete, but actually represents the culmination of 10 years of thought and planning. The staff of the Maricopa Association of Governments (MAG) had long envisioned the preparation of an Urban Atlas with the aim of bringing together a wide range of information used in regional planning, and presenting it in a user-friendly format.
The Maricopa Association of Governments is the regional planning agency for the Phoenix Metropolitan Area and represents 24 cities and towns, two Indian Communities, and Maricopa County. The primary audience for the Urban Atlas was expected to include MAG and member agency staff, elected officials and members of the public.
The Atlas provides valuable information to assist planners in carrying out their responsibilities. For example, the open space map identifies those areas of the region that need to be preserved and excluded from development; while the General Plan land use map identifies the type of development anticipated at build-out. Both of these maps are particularly helpful in evaluating the suitability of new planned area developments. Urban services maps, such as those showing average evening peak period travel speeds, average weekday traffic and PM travel time from downtown Phoenix are particularly useful to transportation planners.
Elected officials find maps in the government services section of the Atlas quite useful in defining the boundaries that are particularly relevant to their constituents. These maps display the corporate boundaries of cities and towns, school district boundaries, state legislative districts, tax districts and public land ownership. Elected officials also can get a better understanding of the composition of the population they represent through the maps in the demographic and employment sections. Particularly relevant are maps that identify the location of single parent households, minorities, the elderly, families, and certain professional occupations.
Finally, the Atlas provides a valuable tool for information-hungry members of the public and especially people who have recently moved to the region. It provides answers to questions such as 'Where will future freeways and transit routes be located?', 'What is the cost of housing?', 'What school districts have the best test scores?', and 'Where are recreational areas located?'.
To produce the Urban Atlas required a clear definition of responsibilities. The Atlas was prepared by a consultant under contract to MAG, managed by MAG staff and coordinated with local, state and federal government agencies. Collaboration among all the parties was essential to ensure the accuracy of the information included in the Atlas and the preparation of a useful, user-friendly and attractive document.
Process
The process for developing the Atlas began with a definition of its organizational structure. The Atlas was divided into six sections arranged in a logical fashion, each designed to present maps and convey information for a particular subject area. The first section, "Physical Features," depicted the natural environment, while the second, "Built Environment," presented maps demonstrating man's imprint on the environment. The subsequent four sections, "Demographics," "Employment," "Government," and "Urban Services," provide an in depth examination of the characteristics of the built environment.
To define the maps to be included in each section, staff developed a preliminary map list, which identified the subject of each map, the base map to be used, the data to be collected and the source of the data. The map list was circulated among MAG staff and member agencies for review and comment. Their input resulted in the addition of some maps and the elimination of others from the map list.
Concurrent with the circulation of the map list, staff worked to achieve concurrence on the base maps to be used for the Atlas. Different map extents were selected based upon the data to be presented. Maps of the entire county were used to display the physical features of the region. But because only 17% of the county's 9200 square miles is developed, maps presenting the built environment and its characteristics were placed on a base map that covered the "Urban Area." The Urban Area was defined as the contiguous part of the region that was developed or forecast to be developed by 2020.
Once the map extents were selected, the features to be included on the maps and the layout of the map had to be determined. An extensive effort was made to portray the mountains in the region in a realistic manner and to develop a map page layout that addressed the basic components of the map such as the legend, text, title, and pagination.
While the composition of the maps were being established, efforts were focused on the cover for the document. Since the cover provides the first impression of the document, it is important that it is attractive and aptly reflects the material inside the Atlas. In order to convey the desert character of the region as well as reflect the urban environment, a photograph of the urban landscape was taken from South Mountain. The picture shows desert vegetation in the foreground and the skyline of Phoenix in the background.
Other photographs were taken by MAG staff to separate the six subject areas of the Atlas and to provide an introduction to the maps in the sections. The photographs that were taken reflected the physical environment, housing developments, government buildings, transportation facilities, employment centers, and congregations of people. These photographs were digitized and then enlarged for inclusion in the Atlas.
Once agreement was reached on the base map and its contents, the cover and the photographs separating the sections, MAG staff then moved to the next phase of the project: the collection of data and the development of draft maps for each of the subject areas to be included in the Atlas.
The data used to prepare the Atlas were derived from other federal, state and local governments as well from MAG databases and private vendors. Where the data obtained was proprietary, MAG signed agreements with the owner of the data agreeing that it would not be distributed in electronic format to other parties.
Variations of two data classification schemes were used to display data with gradient colors in four categories: natural breaks and quartile methods.
The natural breaks method identifies breakpoints between classes using a statistical formula to find groupings and patterns inherent in the data. In the quartile classification method, each class contains the same number of features. Quartile classes are perhaps the easiest to understand, but they can be misleading. Population counts (as opposed to density or percentage) for example, are usually not suitable for quartile classification because of the varying size of the geography and because only a few places are highly populated.
In order to differentiate among the categories, the natural breaks classification scheme was used for the majority of the maps, modified to ensure that the breaks were on rounded numbers, usually factors of ten or one hundred. In addition, if maps were used for comparison purposes, such as percent of population in various age groups, the breaks were kept consistent throughout the map sets. Since gradient colors were used for the demographics and employment sections, the categories were limited to four.
Because the data collected were defined using different levels of geography, such as Census block, block group, zipcode and Traffic Analysis Zone (TAZ), it was necessary to select a common geographical unit for the presentation of the data. For this reason, whenever possible, the data were mapped to TAZ geography. Traffic Analysis Zones are normally defined by streets and/or visible physical features and are the basic unit from which the Maricopa Association of Governments (MAG) prepares socioeconomic and traffic projections.
As with the census geography, as population expands and/or new areas are planned for development, there is a need for MAG to update its TAZ system. The projections prepared in 1993 using the 1990 census as the base used a TAZ system comprised of 1272 zones. The projections prepared using the 1995 Special Census as the base used a TAZ system comprised of 1516 TAZ system developed in 1996. Demographic data derived from the 1990 Census was mapped to the 1272 TAZ system, while demographic data derived from the 1995 Census was mapped to the 1516 TAZ system.
An equivalency file was developed to assist in allocating census data from Census block, block group and enumeration district to Traffic Analysis Zone. Where Traffic Analysis Zones were extremely small, they were combined prior to the allocation taking place.
Draft maps were prepared for each of the subject areas and distributed to MAG staff for initial review and comment. Staff conducted reasonableness checks to ensure the accuracy of the maps and made recommendations for enhancing the appearance of the maps.
Once approved by MAG staff, the maps were circulated among representatives of MAG member agencies as well as any agencies with an intimate knowledge of the subject matter presented on the map. These agencies included, but were not limited to, the Arizona Department of Education, Department of Water Resources, Department of Economic Security, and the State Land Department. Comments received from this process were reviewed and revisions to the maps were made as necessary. MAG staff provided the consultant with a final sign-off on the maps once all the changes were incorporated, signifying that they were ready for final printing.
After all the maps were completed a set of proofs were developed and forwarded to MAG staff for final review. During the review of the set of proofs final revisions were made and the document was forwarded for printing.
Lessons Learned
At the onset of this project, MAG staff felt confident that the organization and work flow of the project was clearly defined in detail. However, during the three years in which the Urban Atlas was prepared, MAG staff learned some valuable lessons. Fortunately, most of these lessons were learned before the Atlas was published. Some lessons learned are presented below:
Feedback from customers of the Urban Atlas has been very positive. They particularly like the size of the Atlas, the content, and the fact that all of the information is available to them in one book. Elected officials, MAG and member agency staff, and non-profit and community organizations in particular have purchased this book. The price, although less than the actual cost to produce the book, might have been a deterrent to others. Few people asked for the associated CD-ROMs of the data that MAG was able to distribute, although MAG continues to get many requests for copies of just one or two pages of the Urban Atlas.
The production of the Urban Atlas was a long, involved process, more
time-consuming than had been anticipated. However, MAG is committed to
ensuring the public has quality data and information for decision-making,
and is already discussing an update of the Urban Atlas when the Year 2000
Census data arrive.
