Planning a GIS
how to go about choosing a GIS
key issues in implementation
why some GIS projects fail
architect of the Canada Geographic Information System in mid 1960s
international consultant
author of standard methodology for GIS planning
Thinking about GIS: Geographic Information Systems Planning for Managers
ESRI Press, Third Edition 2007
"No one else in the world has thought so long about GIS or gathered so much experience in designing, acquiring, and testing GIS software. This book recounts what Roger Tomlinson has learned through many years of consulting with corporations and government agencies large and small, in helping them through the often difficult process of effective GIS planning. He shows how much of the value of planning lies in the process itself -- in the ways in which it encourages organizations to think clearly and deeply about what they do, and about how operations can be made more coherent, efficient, and sustainable. Now in its third edition, the book has established itself as the definitive guide to effective GIS planning, and should be required reading for anyone involved in the planning process, from the boardroom to the production shop."
Scope of GIS projects
single-purpose project
costs paid by the project
no institutional memory
department-wide application
support for a single business need
e.g., city planning department
mailings to impacted property owners
database of properties
maintained for this one purpose
enterprise-wide systems
organization integrated around GIS
many applications in different departments
much cooperation needed
benefits of standard
formats, terminology
people leave but system persists
Who should plan?
specialist consultant
working with staff
staff involved throughout
What to plan?
information products
software
data
hardware
procedures
people
When to plan?
a continuous, dynamic process
trigger factors?
Why plan?
big investment, many years of use
projects most often fail because of poor planning
Ten steps
back out at any stage
1. Consider the strategic purpose
what is the organization about?
strategic plan
mission, goals, strategy, tactics
who does it serve?
all users internal?
general public?
planning is a top-to-bottom examination
GIS as the heart of the enterprise
a formal representation of the organization
its programs
their linkages
2. Plan for the planning
organizational commitment
top down
political commitment
3. Conduct a technology seminar
raise interest in GIS
among staff with no prior background
what is a GIS?
GIS terminology
functions of a GIS
types of data
examples
benefits
outline planning process
4. Describe the information products
what decisions does the organization have to make?
what information would help in making those decisions?
maps, tables, statistics
create drafts of products
working intensively with staff
each product should have an owner
someone responsible
willing to defend
department by department
what functions are needed to create the products?
what software options exist?
what data are needed?
what volumes of data?
how often updated?
what quality?
error tolerance
documentation
perhaps hundreds of products, data sets
staff sign off
Example product definition
National Forest must manage forest land for multiple uses
recreation
needs access by road
wilderness
needs to be away from roads
ROS
Recreation Opportunity Spectrum
a map showing areas classified according to simple rules
Information Product
a map showing forest lands, classified according to accessibility for recreation
a scale of 1:24,000, or larger if possible
the map should show
zones and associated accessibility classes for Forest Service land
base map information - roads, railroads, cities and towns, Forest Service boundary
Data Needed
roads and railroads
from standard 1:24,000 topographic map
available as DLG
Forest Service management area
have been drafted on 1:24,000 topographic map from legal descriptions
shown as many individual areas
most are contiguous but some are not
need to be digitized
city and town boundaries
available in digital form from NSDI
based on 1:24,000 mapping
data will be input as 3 layers
management area boundaries as polygon shapefile (layer A1)
roads and railroads as polyline shapefile (layer B1)
city and town boundaries as area shapefile (layer C1)
1. using the forest service areas data (layer A1)
assign a new attribute FORESTLAND
value = 1 if area is forest service land
0 otherwise
2. dissolve boundaries between areas with the same FORESTLAND value
and merge areas to create new area objects with one attribute - FORESTLAND
call the new layer A2
3. using the transportation map B1, select public access roads only
call the new layer B2
4. generate buffers 0.5 miles wide around all objects in layer B2
call the new layer B3
assign the attribute INHALF a value of 1 for the buffer area, 0 outside
5. generate buffers 1.0 miles wide around all objects in layer B2
call the new layer B4
assign the attribute INONE a value of 1 for the buffer area, 0 outside
6. topologically overlay the objects in layers A2, B3, and B4
some systems may require two steps to overlay three layers
to obtain layer B5 with polygons with the following attributes
FORESTLAND
INHALF
INONE
7. using the city and town boundary layer (C1)
assign a new attribute URBAN
value 1 for areas of cities or towns, 0 otherwise
8. overlay the objects in layer C1 with those in layer B5 to obtain layer B6
adding attribute URBAN to the three attributes in B5
9. assign a new attribute ACCESS to the objects in B6 using the following rules:
0 not forest land (FORESTLAND=0), or forest land and urban (URBAN=1)
1 forest land, non-urban and within 0.5 miles of rail/public road (INHALF=1)
2 forest land, non-urban, outside 0.5 miles but within 1.0 miles of rail/public road (INONE=1)
3 forest land, non-urban, outside 1 mile of rail/public road (INONE=0)
note that the criteria are ordered
in each step only areas that have failed all of the previous tests are considered
10. Dissolve boundaries and merge areas with the same value of ACCESS
call this new layer B7
assign unique ID numbers to each new object
11. Measure the areas of objects (in hectares) in B7 and assign this attribute to each object as AREA
12. Modify attribute ACCESS for cases where ACCESS ="1" and area is greater than 2500 to "1A"
If ACCESS = "1" and AREA >= 2500 then ACCESS="1A"
13. Create a plot showing
Forest Service ownership boundary (layer A2)
All roads and railroads (layer B1)
All cities and towns (layer C1)
Area objects in layer B7, shaded by value of ACCESS attribute and labelled with ID number assigned in step 10
14. Create a list of all area objects in layer B7, showing the following attributes
ID (number assigned in step 10)
ACCESS
AREA
list of functions needed
Assign a new attribute (from existing attributes based on mathematical or Boolean operators)
Dissolve boundaries and merge areas (based on value of specified attribute)
Select objects (based on attributes satisfying mathematical or Boolean operators)
Generate buffers (to a specified width around line objects)
Topologically overlay (two or more layers of area objects to obtain a new layer of area objects)
Measure area (of area objects, assigning values to a new attribute)
Modify an attribute (selectively, based on mathematical or Boolean operators)
Create a plot (of specified classes of objects, showing selected attributes, using various symbol, shade and label options)
Create a list (of a specified class of objects, showing selected attributes, plus subtotals, totals etc.)
once this sequence of operations has been worked out
it is very easy to design a macro which will automatically execute this sequence of steps whenever a layer is updated
could use ModelBuilder
5. Define the system scope
identify common data sets
rank based on importance
Master Input Data List
source, format
digitizing requirements
identify key functions
production schedule
how many products
how often
how big should the system be?
Web based?
architecture?
6. Create a data design
Geodatabase design
assign responsibilities
custodianship
update, quality control
UML
classes, attributes, relationships
7. Choose a logical data model
implement the design
8. Determine system requirements
hardware, software
network design, servers
9. Benefit-cost, migration, and risk analysis
contracts
staffing, training
security, backup
migrating existing legacy systems
10. Implementation plan
timeline, milestones
funding
Request for Proposals
benchmarking