Transcript GIS STANDARDS

GIS STANDARDS
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Introduction
Reasons for standards
Organizations
Types of standards
Implementing standards
INTRODUCTION
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standards are needed as GIS users attempt to
integrate operations with other hardware, GISs
and data sources
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challenge is to get industry, government and
users to implement and promote use of
standards
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many standards are set simply through common
use, major attempts to develop national and
international standards
REASONS FOR STANDARDS
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portability of applications
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data networks
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common environments
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cost of program development
STANDARDS ORGANIZATIONS
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American National Standards Institute
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Digital Cartographic Data Standards Task Force
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Federal Coordinating Committee on Digital
Cartography – Standards Working Group
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Institute of Electrical Electronics Engineers
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International Standards Organization
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Open Software Foundation
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X-Open
TYPES OF STANDARDS
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networking standards – critical to allow
communications between remote computers
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database query standards – SQL is emerging as the
standard
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data exchange standards – governments/private
companies recognize need to exchange data
between different agencies/groups
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several common data exchange formats currently in
use:
DATA EXCHANGE FORMATS
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DEM – Digital Elevation Models
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allows a single attribute per cell
DATA EXCHANGE FORMATS
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DLG – Digital Line Graph
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most widely used format for
exchange of digital
cartographic data in vector
format
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used primarily for coordinate
information, though it does
support alphanumeric
attributes
DLG Roads
DATA EXCHANGE FORMATS
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GBF/DIME – Geographic Base File/Dual
Independent Map Encoding
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allows both coordinate and attribute data
DATA EXCHANGE FORMATS
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TIGER – Topologically Integrated Geographic
Encoding and Referencing
support
pre-census
geographic and
cartographic
functions in
preparation for the
1990 Census
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assist in the
analysis of the data
as well as to
produce new
cartographic
DATA EXCHANGE FORMATS
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SIF – Standard Interchange Format (Intergraph)
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popular data exchange format for many GIS packages
DXF – Digital eXchange Format
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popular exchange format for many GIS packages to
transfer with CAD
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specially formatted text file that can be viewed and
modified with any text editor
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organized into different sections – header, table, block,
etc.
IMPLEMENTING STANDARDS
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Start-up Costs
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implementation of standard can incur substantial costs
(money and time)
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major short-term costs related to user training and
reprogramming software
Management Support
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needs to recognize the positive impacts of standards
on productivity and system costs (plus commitment of
short-term costs)
IMPLEMENTING STANDARDS
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Technical Tradeoffs
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tradeoffs between functionality and performance
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standards provide for broad functionality
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adopting standard operating system provides access to large
library of existing applications
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standards do not allow fine tuning to specific hardware
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some de facto standards are neither efficient nor the
best available
IMPLEMENTING STANDARDS
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Potential for Security Risks
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wide availability of common operating systems allow
for misuse and exploitation
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spread of computer viruses depends on common operating
systems
Innovation
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broadly accepted standards make it very difficult to
introduce innovations
STANDARDS
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majority of standards effort in GIS to date has
concerned data formats
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missing – standard of data models that would provide
standard ways of representing geographic phenomena
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should there be standard resolutions for DEM?
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should there be standards of vertical accuracy?
missing – standards of data accuracy for GIS
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map accuracy standards deal only with cartographic features
STANDARDS
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data may be written into standard format for transfer,
but it may still be virtually meaningless without
extensive documentation
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standards would provide GIS user with expectations
about the reliability of the database as a window on
the world
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rather than on source documents, on transferred databases