A Conceptual Model for Placename

Geography in GIS

Scott MorehouseDirector, Software Development

ESRI

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Geography of Places - A Trivial problem?

“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!?

Lat Lon Name- - -- - -- - -

Select Lat, Lon from Gazetteer where Name = ‘Los Angeles’

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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.

Places 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 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”)

Places can have fuzzy names or descriptions (“White House” = “1600 Pennsylvania Avenue” = “1600 Penn. Ave”)

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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

Standardize

Score & Choose

Search for matches and construct

candidates

Component, component,...Candidate

List

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?