Transcript DGIE_Morehouse

A Conceptual Model
for Placename
Geography in GIS
Scott Morehouse
Director, Software Development
ESRI
Geography of Places - A Trivial problem?
Lat
-
Lon
-
Name
-
Select Lat, Lon from Gazetteer
where Name = ‘Los Angeles’
“Oh yeah, add something for variant spellings… and
maybe a time stamp… and I guess we need a
provenance… and standard word lists… and...
Philosophy of Geography to the rescue!?
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What is a Place? What are Place names?

Places are not simply “things in space”, they are a part
of space itself. Places are not features!
 There
are an infinite number of places in space and there are
many ways to define places in space.
can be the space occupied by a named thing (“Lake
Ontario”)
 Places
can be described as well as named. (“north shore of Long
Island”)
 Places
 Places
exist in a context of language, time, geographic
hirerarchy, and descriptive syntax. The same place name can
mean different locations, depending on context.
 Places
can have fuzzy location (“Rocky Mountains”)
can have fuzzy names or descriptions (“White House” =
“1600 Pennsylvania Avenue” = “1600 Penn. Ave”)
 Places
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Examples of Places
Rocky Mountain National Park
42
813 Clifton Av., Pittsburgh, PA Luck Star Mine near Blythe
Los Angeles, California
Mississippi River
90210
Mississippi River Basin
64º 23’ 18º 52’
Speke Expedition, Day 23
187,322 E 23,543 N
Patagonia
North Fork, Kern River
(909)555-1212
Bellows Falls
I-10 233.5
T14N R6W S4 NW 1/4
Hollywood & Vine
Potomac River, Chain Bridge + 3.2
Are these names? Or
descriptions? How much
can a poor gazetteer do?
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A Framework for Locating Places
Address
Location
Parse
Score &
Choose
Component, component,...
Candidate
List
Standardize
Search for
matches and construct
candidates
Database of named things,
relationships, and standard
address components
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Interesting Questions

How much parsing, candidate finding, and scoring is the
responsibility of the gazetteer? Is the gazetteer simply the
database of standard name components?



Are gazetteer standards intended for developers of location services or
for direct use by end users?
How much context for names is necessary?

Each style of address has an implied context - postal geography,
administrative geography, land survey, etc.

How much context should be explicitly represented in the database vs.
discovered “on the fly”? Should we attempt to model things like “SFO
is in San Francisco is in Bay Area is near the Delta”? Or use
generalized spatial search?
Is a “one size fits all” standard applicable or are there different
standards for different types of place description?
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