In Project: Used many spatial db- parcel, street, rr, etc. that were associated to attribute data. opened different types of data formats- dbf files (voters) Analysis through various GIS functions: geocoding- voters by address to parcel & interpolation
Used many spatial db- parcel, street, rr, etc. that
were associated to attribute data.
opened different types of data formats- dbf files (voters)
Analysis through various GIS functions:
geocoding- voters by address to parcel & interpolation
heads-up digitizing- draw study area polygon
editing- move or reshape the TIGER based streets, create path
to nearest bus stop from chosen site
relational join- attribute sql of parcel polygons to Auditor data
linked by common field- ppn
derived column calculation- area function in sql
spatially combined objects based on column - associated parcels
attribute sql- of land use that is vacant
buffering- 200 ft from toxic sites.
spatial query- spatial sql parcel object within toxic buffer
use Vertical Mapper to determine slope of sites
thematic mapping- dot density of population, pie of vacant &
maps- final sites, etc
photos- of final sites, aerial registration
browsers- attribute table data of selected sites
GIS Definition Diagram
Issues resulting from releasing GIS data to public:
Example 1: Person contacts city dept. and demands map of all Rotweiler dog
locations and owners within the city. City worker provides the map.
City is later sued. Homeowners near dog locations blame city for releasing map,
saying that it lowered home values due to the map.
Example 2: Contractor is building new structure. Must dig up area under road
and building. Contractor asks city dept. for map of infrastructure (gas,electric,
& water lines). City worker provides the map.
Contractor digs with back-hoe, ruptures gas line, big fire, lots of damage, 1 death
and a huge lawsuit.
What data should be made available to public?
Determined by law; Public vs Confidential; Freedom of Information Act
What format to release the data?
Paper report or map or must you provide digitally??
Who is liable for incorrect maps or data?
Disclaimers on any released data- “Use at your own risk”
Who should be responsible to make decisions on what should be released?
Lawyers, politicians, technical or scientific staff??
Releasing data has consequences:
Technical- request may be to difficult to extract and program. Thus, too costly.
Legal- what must be released? What data format? What is liability in releasing?
Economic- impact on economy from the release of data. (ie. lower housing value
due to the vicious dog location map)
Political- city leaders, managers, etc. can lose jobs by releasing the data
Bottom line: Producing, then disseminating data to the public can be dangerous.
Be responsible & prepared-
Review GIS issues; determine how data will be released;
Have disclaimers and supply metadata;
Have system in place to authorize the release of data;
Get advice of city lawyers
GIS software usage in
Government for US- 2000
ESRI has most government use
MapInfo has higher usage in
private business sector
How do I determine what software to
purchase for my company, agency,
Evaluation of GIS Software
Every few years, one of the GIS magazines
evaluates the GIS software on the market.
Lists the functions of each.
Can help you to evaluate the software.
Displays in “Consumer Reports” style
to evaluate GIS Software.
Hardware Requirements for GIS
Most of the PCs or laptops on the market can handle the majority of GIS tasks.
Here are some guidelines:
- IBM compatible PC or laptop
- Processor – Pentium (dual core)
- Operating System– Windows XP , Windows 2000, Windows 2003,
Vista, Windows 2007, Windows 2010
- Memory– minimum= 128 MB RAM , recommended = 4 GB
- Hard Drive– Fast EIDE 2 or SCSI Interface with 2 GB or better.
Data- 2GB or more (more is better, like 50 or 100 GB)
( Note: size for software and data files in this class is
less than 1GB)