Fundamental Issue:
How do diverse groups share information?
Competing theoretical approaches
An example
Geographic Information Technology
as applied to:
Wetlands Inventory [USA]
Conclusions
Sharing technology with a larger community of users involves a process of explaining the technology, what it does, and how to use it.
· Diffusion
One origin, dispersal without alteration
fails to account for spatio-temporal process
· Paradigms
Recognize periods of different models
still has unrealistic (universal) spatial character
· Beyond paradigms:
Actor Networks: incomplete translations
Trading Zone: interlanguage at meeting point
Boundary Objects: agreement to disagree
Geographic Information Systems (GIS)
One (bland) definition:
A system of hardware, software, data, people, organizations
and institutional arrangements for collecting, storing, analyzing
and disseminating information about areas of the earth. (Dueker
and Kjerne, 1989, p. 7-8)
My (longer-winded) definition:
The organized activity by which people
· measure aspects of geographic phenomena and processes;
· represent these measurements, usually in the form of
a computer database, to emphasize spatial themes, entities, and
relationships;
· operate upon these representations to produce more measurements
and to discover new relationships by integrating disparate sources;
and
· transform these representations to conform to other frameworks
of entities and relationships.
These activities reflect the larger context (institutions and
cultures) in which these people carry out their work. In turn,
the GIS may influence these structures." (Chrisman, 1997
Exploring GIS, p. 5)
GIS in use
integration of diverse sources
Two paths to integration
geometric superposition
(map overlay)
Calculate the connection between "layers"
Brute force technique: discovers inconsistency
schema integration
use linguistic metadata to find formal equivalence
Highly dependent on common terminology;
systems analysts constructing their interlanguage?
On to some examples...
Wastelands versus Wetlands
Two distinct mandates produce independent maps.
Wastelands
(Department of Revenue) reduce tax assessed for ownership
parcels found to have "swamp and waste" [dates from
1930s]
Wetlands
(Department of Natural Resources) regulate development through
zoning of land found to support certain ecological functions [dates
from 1970s]
Nearly total incommensurability
Wastelands: estimated area attached to parcels
Wetlands: photointerpreted polygons
Result of overlay analysis
number of parcels
Wastelands assessed, Wetlands not mapped 16
Wastelands assessed, only Farmed Wetlands mapped 3
Wastelands exceed Wetlands by more than 20% 36
Wastelands match Wetlands within 20% 19
Wetlands exceed Wastelands by more than 20% 7
Wetlands mapped, Wastelands not assessed 38
Total non-exempt parcels with Wetlands or Wastelands 119
Table 1: Comparison of Wetland Inventory to Wasteland assessment
Source: Sullivan, Chrisman and Niemann, 1985 Table 1
Bottom line: social and political processes do not detect even the most complete mismatch between taxes and regulations when sufficiently clouded by distinct expertises and established epistemes.
Comparing Wetland Inventories
Wicomico County, Maryland
Wetlands Subcommittee, Federal Geographic Data Committee
[at: http://www.usgs.gov/wetlands/]
8 sources available
2 discarded as incommensurable
(points not polygons)
2 begged out due to scale or technique
4 sources compared.
0 data sets 1 data set 2 data sets 3 data sets 4 data sets
FWS-NWI 91796 653 2099 4789 5444
MD-WRA 91796 1531 3838 6292 5444
NOAA-CCAP 91796 7798 11366 6001 5444
NRCS-WI 91796 27140 13205 5649 5444
Total (acres) 91796 37122 15254 7577 5444
Totals (%) 58.4% 23.6% 9.7% 4.8% 3.5%
Table 2: Agreement between wetland mapping sources in acres
based on (Shapiro 1995 Table 4, p.38) [The column "0 data
sets" records area never classified as wetlands; the last
column was classified in all four sources.]
Can standards work?
Two sources used
same classification system (Cowardin et al.)
same airphoto techniques
(different dates)
Palustrine Lacustrine Riverine Estuarine Upland Total
Palustrine 7214 33 8 15 7311 14581
Lacustrine 32 458 0 0 58 548
Riverine 178 5 567 41 61 852
Estuarine 24 0 1 1044 48 1117
Upland 3193 49 29 74 136705 140050
Total 10641 545 605 1174 144183 157148
Table 3: Comparison of wetlands mapped by NWI and MD WRA
(Rows: MD WRA; Columns FWS NWI; all figures in acres; shading
for agreement)
Graphics at: http://www.usgs.gov/wetlands/task3a.html#spatial
Change is an issue, but it is not this large.
Accuracy assessment in field: ambiguous results
Remedies proscribed
Standards for classification
"Manual Wars" of 1980s: political intervention (Ronald
Reagan, Dan Quayle) to make wetlands less restrictive.
Cowardin established as FGDC standard,
over objections of Corps of Engineers
No sign of a trading zone (interlanguage)
each side sticks to its definitions, builds stronger networks
of allies;
diplomacy by other means...
Role of time (and bureaucratic self-preservation)
Some of the claims:
NWI uses photointerpretation because when they started (1970s),
remote sensing was not proven, now they must remain consistent.
NOAA-CCAP uses remote sensing for speed.
NRCS uses soil maps to peel back human disturbance to the (geological)
record of wetland environments
Corps of Engineers does what they are mandated by (prior) statutes.
NRCS does what Congress directs (of course they tell Congress
how they could carry out the surveys...)
NWI fixed the inconsistency with Maryland by adopting Maryland's
map.
"No net loss" (to quote some Presidents) of a resource
that MUST come and go with hydrological conditions...
"Wetland":
trading zone or boundary object?
No sign of an interlanguage in this situation
Multidisciplinary use of geographic technology
incomplete translations;
frustrated negotiations
Swamp or waste?
locally defined, hard to document, hard to share
not a subject for the unwary.
Version of 27 October 1999