A critical step in developing a GIS is to assess the needs
and requirements for a potential system. This is a common problem
in systems design of all kinds (information systems are just one
example, and GIS is probably less formalized than most other applications).
It may be important to distinguish "system requirements"
(choice of specific hardware and software) from the more conceptual
"user needs assessment" that should precede and guide
the system requirements.
One sequence to implement a GIS (simplified from Ventura and other
sources):
Table 10-1: Sequence of steps to implement a GIS
0. Preliminaries Create awareness
Day 1: Agreement to begin implementation process1. Needs Assessment
[Performed by interviews, surveys, reading old reports, etc.]
Data oriented sources, flows, transactions Process oriented operations, transformations Product oriented maps, graphs, tables, reports, decisions 2. Requirements Analysis
[Match needs to current technology]
Identify technical constraints (long-term) System Design specify data models 2.5 Results in an Implementation Plan
Generate Request for Proposals (RFP) (short term) Evaluate responses to RFP Select vendor [qualifications of vendors in next lecture] Benchmark [or pilot project] measures performance of system 3. Construction
Pilot Project/ Demonstration trial run of proposed design Conversion digitize existing records; convert operations Quality Control evaluate information in system 4. Reevaluation (continual?)
[return to start? (0 or 1)]
Many systems are designed in an opportunistic way, letting
the technology rule.
You can only do what the software permits you to do, after all.
Vision also tends to be limited to replacement of current functions.
In this way, the software and the implementation are like a dysfunctional relationship where no one asks any of the hard questions.
attempt to develop generic data model for municipalities
Matrix of tasks requiring different data sources (will this
really apply across all municipalities? if it does, then there
is little need for consultants like Carol Freedman... fortunately
it didn't work, each case requires reexamination)
selected from (Dangermond and Freedman, 1984, p.13 Table 1)
a stream in the Software Engineering literature
Examine work currently performed, looking for a common step of
basic "tasks" that could be rearranged, or served differently.
Steve Ventura (U. Wisconsin - Madison) 1991
Implementation of LIS in Local Government (no longer $10
from Wisc. State Cartographer)
Distinguishes conceptual assessment, detailed assessement, system
requirements
what kind of data are required
why is it used? how is it used?
what kind of results do users expect?
Techniques:
Develop requirements:
FGDC Framework
project (attempt to assure common content nationwide)
Basis of this goes back to the Mapping
Sciences Committee report 1990: Spatial Data Needs: the Future
of the National Mapping Program, the 1993 report "Towards
a Coordinated Spatial Data Infrastructure of the Nation"
and later
reports.
GIS Implementation was a part of US national political agendas
in the Clinton-Gore era, but Homeland Security means a shift...
In fact, the military mapping establishment (NIMA
now NGA) is moving into the mapping of 130 metropolitan areas.
What is Geospatial Intelligence anyway?