Joseph K. Berry
Keck Visiting Scholar in Geosciences, University of Denver
Berry and Associates // Spatial Information Systems, Inc.
Note: This paper is a distillation of several keynotes,
presentations and papers; see Author’s Note at the end of the paper.
<Click here> for a printer-
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The early 1970's saw computer mapping automate
map drafting. The points, lines and areas defining geographic features on a map
are represented as an organized set of X, Y coordinates. These data drive pen
plotters that can rapidly redraw the connections at a variety of colors,
scales, and projections with the map image, itself, as the focus of the
processing.
The pioneering work during this period
established many of the underlying concepts and procedures of modern GIS
technology. An obvious advantage with computer mapping is the ability to change
a portion of a map and quickly redraft the entire area. Updates to resource
maps which could take weeks, such as a forest fire burn, can be done in a few
hours. The less obvious advantage is the radical change in the format of mapped
data— from analog inked lines on paper, to digital values stored on disk.
During 1980's, the change in data format and
computer environment was exploited. Spatial database management systems
were developed that linked computer mapping capabilities with traditional
database management capabilities. In
these systems, identification numbers are assigned to each geographic feature,
such as a timber harvest unit or ownership parcel. For example, a user is able to point to any
location on a map and instantly retrieve information about that location. Alternatively, a user can specify a set of
conditions, such as a specific forest and soil combination, then
direct the results of the geographic search to be displayed as a map.
Early in the development of GIS, two alternative
data structures for encoding maps were debated.
The vector data model
closely mimics the manual drafting process by representing map features
(discrete spatial objects) as a set of lines which, in turn, are stores as a
series of X,Y coordinates. An alternative structure, termed the raster data model, establishes an
imaginary grid over a project area, and then stores resource information for
each cell in the grid (continuous map surface).
The early debate attempted to determine the universally best
structure. The relative advantages and
disadvantages of both were viewed in a competitive manner that failed to
recognize the overall strengths of a GIS approach encompassing both formats.
By the mid-1980's, the general consensus within
the GIS community was that the nature of the data and the processing desired
determines the appropriate data structure.
This realization of the duality of mapped data structure had significant
impact on geographic information systems.
From one perspective, maps form sharp boundaries that are best
represented as lines. Property
ownership, timber sale boundaries, and road networks are examples where lines
are real and the data are certain. Other
maps, such as soils, site index, and slope are interpretations of terrain
conditions. The placement of lines
identifying these conditions is subject to judgment and broad classification of
continuous spatial distributions. From
this perspective, a sharp boundary implied by a line is artificial and the data
itself is based on probability.
Increasing demands for mapped data focused
attention on data availability, accuracy and standards, as well as data
structure issues. Hardware vendors
continued to improve digitizing equipment, with manual digitizing tablets
giving way to automated scanners at many GIS facilities. A new industry for map encoding and database
design emerged, as well as a marketplace for the sales of digital map products. Regional, national and international
organizations began addressing the necessary standards for digital maps to
insure compatibility among systems. This
era saw GIS database development move from project costing to equity investment
justification in the development of corporate databases.
As GIS continued its evolution, the emphasis
turned from descriptive query to prescriptive analysis of maps. If early GIS users had to repeatedly overlay
several maps on a light-table, an analogous procedure was developed within the
GIS. Similarly, if repeated distance and
bearing calculations were needed, the GIS system was programmed with a
mathematical solution. The result of
this effort was GIS functionality that mimicked the manual procedures in a
user's daily activities. The value of
these systems was the savings gained by automating tedious and repetitive
operations.
By the mid-1980's, the bulk of descriptive query
operations were available in most GIS systems and attention turned to a
comprehensive theory of map analysis.
The dominant feature of this theory is that spatial information is
represented numerically, rather than in analog fashion as inked lines on a
map. These digital maps are frequently
conceptualized as a set of "floating maps" with a common registration,
allowing the computer to "look" down and across the stack of digital
maps. The spatial relationships of the
data can be summarized (database queries) or mathematically manipulated
(analytic processing). Because of the
analog nature of traditional map sheets, manual analytic techniques are limited
in their quantitative processing.
Digital representation, on the other hand, makes a wealth of
quantitative (as well as qualitative) processing possible. The application of this new theory to mapping
was revolutionary and its application takes two forms—spatial statistics and
spatial analysis.
Meteorologists and geophysicists have used spatial statistics for decades to
characterize the geographic distribution, or pattern, of mapped data. The statistics describe the spatial variation
in the data, rather than assuming a typical response is everywhere. For example, field measurements of snow depth
can be made at several plots within a watershed. Traditionally, these data are analyzed for a
single value (the average depth) to characterize an entire watershed. Spatial statistics, on the other hand, uses
both the location and the measurements at sample locations to generate a map of
relative snow depth throughout the watershed.
This numeric-based processing is a direct extension of traditional
non-spatial statistics.
Spatial analysis applications, on the other hand, involve
context-based processing. For example,
forester’s can characterize timber supply by considering the relative skidding and
log-hauling accessibility of harvesting parcels. Wildlife managers can consider
such factors as proximity to roads and relative housing density to map human
activity and incorporate this information into habitat delineation. Land
planners can assess the visual exposure of alternative sites for a facility to
sensitive viewing locations, such as roads and scenic overlooks.
Spatial mathematics has evolved similar to
spatial statistics by extending conventional concepts. This "map algebra" uses sequential
processing of spatial operators to perform complex map analyses. It is similar to traditional algebra in which
primitive operations (e.g., add, subtract, exponentiate) are logically
sequenced on variables to form equations.
However in map algebra, entire maps composed of thousands or millions of
numbers represent the variables of the spatial equation.
Most of the traditional mathematical
capabilities, plus an extensive set of advanced map processing operations, are
available in modern GIS packages. You
can add, subtract, multiply, divide, exponentiate, root, log, cosine,
differentiate and even integrate maps.
After all, maps in a GIS are just organized sets of numbers. However, with map-ematics,
the spatial coincidence and juxtaposition of values among and within maps
create new operations, such as effective distance, optimal path routing, visual
exposure density and landscape diversity, shape and pattern. These new tools
and modeling approach to spatial information combine to extend record-keeping systems
and decision-making models into effective decision support systems.
The previous discussion focused on early GIS
technology and its expressions as three evolutionary phases— Computer Mapping (70s),
Spatial Database Management (80s) and Map Analysis/Modeling (90s). These efforts established the underlying
concepts, structures and tools supporting modern geotechnology. What is radically different today is the
broad adoption of GIS and its new map forms.
In the early years, GIS was considered the
domain of a relatively few cloistered techno-geeks “down the hall and to the
right.” Today, it is on everyone’s desk,
PDA and even cell phone. In just three
decades it has evolved from an emerging science to a fabric of society that
depends on its products from getting driving directions to sharing interactive
maps of the family vacation.
In fact, the U.S. Department of Labor has
designated Geotechnology as one of the three “mega-technologies” of the 21st
century—right up there with Nanotechnology and Biotechnology. This broad acceptance and impact is in large
part the result of the general wave of computer pervasiveness in modern
society. We expect information to be
just a click away and spatial information is no exception.
However, societal acceptance also is the result
of the new map forms and processing environments. Flagship GIS systems, once heralded as
“toolboxes,” are giving way to web services and tailored application solutions. There is growing number of websites with
extensive sets of map layers that enable users to mix and match their own
custom views. Data exchange and
interoperability standards are taking hold to extend this flexibility to
multiple nodes on the web, with some data from here, analytic tools from there
and display capabilities from over there.
The results are high-level applications that speak in a user’s idiom
(not GIS-speak) and hide the complexity of data manipulation and obscure
command sequences. In this new
environment, the user focuses on the spatial logic of a solution and is hardly
aware that GIS even is involved.
Another characteristic of the new processing
environment is the full integration the global positioning system and remote
sensing imagery with GIS. GPS and the
digital map bring geographic positioning to the palm of your hand. Toggling on and off an aerial photograph
provides reality as a backdrop to GIS summarized and modeled information. Add ancillary systems, such as robotics, to
the mix and new automated procedures for data collection and on-the-fly
applications arise.
In addition to the changes in the processing
environment, contemporary maps have radical new forms of display beyond the
historical 2D planimetric paper map.
Today, one expects to be able to drape spatial information on a 3D view
of the terrain. Virtual reality can
transform the information from pastel polygons to rendered objects of trees,
lakes and buildings for near photographic realism. Embedded hyperlinks access actual photos,
video, audio, text and data associated with map locations. Immersive imaging enables the user to
interactively pan and zoom in all directions within a display.
4D GIS (XYZ and time) is the next major
frontier. Currently, time is handled as
a series of stored map layers that can be animated to view changes on the
landscape. Add predictive modeling to
the mix and proposed management actions (e.g., timber harvesting and subsequent
vegetation growth) can be introduced to look into the future. Tomorrow’s data structures will accommodate
time as a stored dimension and completely change the conventional mapping
paradigm.
CRITICAL ISSUES (Future Challenges)
The technical hurdles surrounding GIS have been
aggressively tackled over the past four decades. Comprehensive spatial databases are taking form,
GIS applications are accelerating and even office automation packages are
including a "mapping button."
So what is the most pressing issue confronting GIS in the next
millennium?
Calvin, of the Calvin and Hobbes comic strip,
puts it in perspective: "Why waste time learning, when ignorance is
instantaneous?" Why should time be
wasted in GIS training and education?
It's just a tool, isn't it? The
users can figure it out for themselves.
They quickly grasped the operational concepts of the toaster and indoor
plumbing. We have been mapping for
thousands of years and it is second nature.
GIS technology just automated the process and made it easier.
Admittedly, this is a bit of an overstatement, but it does set the stage for
GIS's largest hurdle— educating the masses of potential users on what GIS is
(and isn't) and developing spatial reasoning skills. In many respects, GIS technology is not
mapping as usual. The rights, privileges
and responsibilities of interacting with mapped variables are much more
demanding than interactions with traditional maps and spatial records.
At least as much attention (and ultimately,
direct investment) should go into geospatial application development and
training as is given to hardware, software and database development. Like the automobile and indoor plumbing, GIS
won't be an important technology until it becomes second nature for both
accessing mapped data and translating it into information for decisions. Much more attention needs to be focused
beyond mapping to that of spatial reasoning, the "softer," less
traditional side of geotechnology.
GIS’s development has been more evolutionary,
than revolutionary. It responds to
contemporary needs as much as it responds to technical breakthroughs. Planning and management have always required
information as the cornerstone. Early
information systems relied on physical storage of data and manual
processing. With the advent of the
computer, most of these data and procedures have been automated. As a result, the focus of GIS has expanded
from descriptive inventories to entirely new applications involving
prescriptive analysis. In this
transition, map analysis has become more quantitative. This wealth of new processing capabilities
provides an opportunity to address complex spatial issues in entirely new ways.
It is clear that GIS technology has greatly changed our perspective of a
map. It has moved mapping from a
historical role of provider of input, to an active and vital ingredient in the
"thruput" process of decision-making. Today's professional is challenged to
understand this new environment and formulate innovative applications that meet
the complexity and accelerating needs of the twenty-first century.
Author's Note: This paper is a
distillation of several keynotes, presentations and papers. Online
references include:
§
Spatial
Reasoning in a World of Maps, GeoAlberta
Conference, Edmonton, Alberta, Canada, May, 2006. Keynote Address.
http://www.innovativegis.com/basis/present/GeoAlberta06/GeoAlberta06.htm
§
Getting
Your Arms Around Geospatial Technology, Geospatial
Information Systems and Science Forum,
§
GIS Technology
in Environmental Management: A Brief History, Trends and Probable Future, Global Environmental
Policy and Administration, Soden and Steel editors,
Marcel Dekker Publishers, 1999, pgs. 49-76. J.K. Berry. Book chapter.
http://www.innovativegis.com/basis/present/Global/global3.htm
§
Where
Is GIS? — Driving Forces,
Trends and Probable Future of
Additional papers, presentations and other materials on GIS concepts, considerations and procedures are available online at www.innovativegis.com/basis.