Points of Interest Core

Table of Contents

• 1. Introduction
• 2. Terminology
• 3. POI Data Model
  • 3.1 Geo-reference
    • 3.1.1 Center
    • 3.1.2 Navigation Point
    • 3.1.3 Address
    • 3.1.4 Route
    • 3.1.5 Area
    • 3.1.6 Object
    • 3.1.7 Undetermined
    • 3.1.8 Relative
    • 3.1.9 Map
  • 3.2 Location
    • 3.2.1 Contains
  • 3.3 Relationship primitive
    • 3.3.1 contained-within
    • 3.3.2 contains
    • 3.3.3 adjacent-to
  • 3.4 string primitive
  • 3.5 Label primitive
  • 3.6 ID primitive
  • 3.7 Categorization primitive
  • 3.8 meta data primitive
  • 3.9 Time primitive
• 4. XML Syntax
  • 4.1 XML Notation
  • 4.2 <pois> element
  • 4.3 <poi> element
  • 4.4 Representing coordinates
    • 4.4.1 <point> element
  • 4.5 <location> element
    • 4.5.1 <center> element
    • 4.5.2 <address> element
    • 4.5.3 <navigation-point> element
    • 4.5.4 <area> element
    • 4.5.5 <object> element
    • 4.5.6 <undetermined> element
    • 4.5.7 <relative> element
    • 4.5.8 <map> element
  • 4.6 <relationship> element
  • 4.7 <label> element
  • 4.8 id representation
  • 4.9 <category> element
  • 4.10 Meta-data
  • 4.11 <time> element
  • 4.12 XML Example
  • 4.13 XML Schema
• A. Use Cases
• B. Acknowledgements
• C. References
  • C.1 Normative references
  • C.2 Informative references

1. Introduction

In general terms, a "point of interest" is a location about which information is available. A POI can be as simple as a set of coordinates and an identifier, or more complex such as a three dimensional model of a building with names in various languages, information about open and closed hours, and a civic address. POI data has many uses including augmented reality browsers, location-based social networking games, geocaching, mapping, and navigation systems.

POI data has traditionally been exchanged in proprietary formats via various transports. This specification defines a flexible, lightweight, extensible POI data model, and one normative syntax for the data model. This will enable content publishers to effectively describe and efficiently serve and exchange POI data. In addition to the data model and format, this specification includes best practices for how to organize and serve POIs on the Web.

To achieve these goals, this document describes a generic data model and one normative format. This format is based on XML and is likely insufficient to cover all POI use cases, therefore, it is expected that the data model will be mapped to other formats, such as JSON, GML, RDF, GeoRSS, or HTML.

This section will be fleshed out in more detail for the next draft

2. Terminology

The term points of interest is used in a broad sense in this specification to refer to a loosely coupled and inter-related set of terms: locations, POIs and places.

This section is primarily based on the wiki home page definition of POI.

Location

The term location is used to refer to a geographical construct, a physically fixed point, typically on the surface of the Earth (relative to WGS-84), though locations can be relative to another coordinate system. Locations can be a single point, a centroid, a minimum bounding rectangle, or a set of vectors. A location should be persistent over time and does not change.

OGC has suggested the following changes to the definition of location:
"FYI, Point of Interest is defined in the OGC Open Location Services standard as:
A location (with a fixed position) where one can find a place, product or service, typically identified by name rather than by address and characterized by type, which may be used as a reference point or a target in a location based service request, e.g., as the destination of a route.
The definition for “Location” should be harmonized with ISO standards terms and definitions. Also, a specified coordinate reference system (WGS 84) should not be mentioned in a definition. The specification and handling of CRS should be later in the document. So, the definition of Location becomes:
Location: Identifiable geographic place . Typically a location is a physically fixed point, typically on the surface of the Earth, though locations can be relative to other, non-earth centric coordinate reference systems. Locations can be a single point, a centroid, a minimum bounding rectangle, or a set of vectors. A location should be persistent over time and does not change. "

Points of Interest

Unlike the term location, the term POI is a human construct. POIs describe information about locations such as name, category, unique identifier, or civic address.

Places

A place is also a human construct which typically has a coarse level of spatial granularity. Places are generally larger scale administrative constructs, either informally or formally defined. Countries, states, counties, districts, neighborhoods and postal codes or telephone area codes are all places. Places are also informally or colloquially defined, such as the Home Counties in the United Kingdom and the Bay Area in the United States.

Places have spatial relationships; with parents, children, adjacencies and contained by semantics. Places also have the same attribute set as POIs, although with differing interpretations based on scale; for example, the address of a Place or its URI would refer to the address of the administrative or governing body of the place.

A place typically contains multiple POIs and can also be coterminous with a POI. In the former case, a place, such as a city or a neighborhood, will contain multiple POIs. In the latter case, a place and a POI will occupy the same position and extent, such as in the case of Yellowstone National Park, which is both a Place and a POI.

Primitive

The term primitive refers to the basic components of a POI. For example, a POI could be a collection of location and category primitives.

Coordinate

The term coordinate refers to one of a sequence of n numbers designating the position of a point in n-dimensional space .

Coordinate Reference System

The term coordinate reference system refers to a coordinate system that is related to an object by a datum .

Coordinate System

The term coordinate system refers to a set of mathematical rules for specifying how coordinates are to be assigned to points .

Datum

The term datum refers to a parameter or set of parameters that define the position of the origin, the scale, and the orientation of a coordinate system .

Geolocation

The term geolocation refers to the identification of the real world geographic location of an object.

Point

The term point refers to a 0-dimensional geometric primitive, representing a position .

Position

The term position refers to a data type that describes a point or geometry potentially occupied by an object or person .

Route

The term route refers to a sequence of links and / or partial links that describe a path, usually between two positions, within a network .

3. POI Data Model

The following primitives can be combined to represent a POI.

This section will have a graphic representing the data model for next draft

4. XML Syntax

Even more so than the rest of this document, this section is a straw man proposal, so please treat it as such!

This section describes an XML syntax to represent the data model.

<?xml version="1.0" encoding="UTF-8"?>
<pois>
	<poi id="StataCenter" xml:lang="en-US" >

		<label primary="true" xml:lang="en-US">Stata Center</label>
		<label primary="true" xml:lang="es">Stata Centro</label>
		<label>Ray and Maria Stata Center</label>
		<label>Building 32</label>
		<label>Gates Tower</label>
		<label>Dreyfoos Tower</label>
		
		<location id="location1">
			<point latitude="42.360890561289295" longitude="-71.09139204025269"/>

			<point id="mainpoint" latitude="27.174799" longitude="78.042111" altitude="10m"/>
			
			<center latitude="27.174799" longitude="78.042111"/>
			
			
			<route>
				<point order="0" latitude="42.360890561289295" longitude="-71.09139204025269"/>
				<point order="1" latitude="42.361176" longitude="-71.09018"/>
				<point order="2" latitude="42.36272976137689" longitude="-71.09049081802368"/>
				<point order="3" latitude="42.36318955298668" longitude="-71.09677791595459"/>
				<point order="4" latitude="42.363617631805496" longitude="-71.10156297683716"/>
				
			</route>

			<area>
				<point order="0" latitude="42.360890561289295" longitude="-71.09139204025269"/>
				<point order="1" latitude="42.361176" longitude="-71.09018"/>
				<point order="2" latitude="42.36272976137689" longitude="-71.09049081802368"/>
				<point order="3" latitude="42.36318955298668" longitude="-71.09677791595459"/>
				<point order="4" latitude="42.363617631805496" longitude="-71.10156297683716"/>
				<point order="5" latitude="42.360890561289295" longitude="-71.09139204025269"/>
			</area>
			
			<undetermined/>
			
			<relative location-id="mainpoint" distance-from="10m" bearing-to="20" relative-height="10m"/>

		</location>
		<category scheme="http://www.census.gov/cgi-bin/sssd/naics/naicsrch?search=2007%20NAICS%20Search&code=611310">
			<name xml:lang="en-US">Colleges, Universities, and Professional Schools</name>
			<association type="child-of" reference="http://www.census.gov/cgi-bin/sssd/naics/naicsrch?search=2007%20NAICS%20Search&code=6113"/>

		</category>

	</poi>
	<poi id="w3c">
		<label primary="true">World Wide Web Consortium</label>
		<label>W3C</label>
		<label>W3</label>
		<location>
			
		</location>
		
		<relation type="contained-by" id="#StataCenter"/>
		
		<!-- category using a scheme -->
		<category scheme="http://www.census.gov/cgi-bin/sssd/naics/naicsrch?search=2007%20NAICS%20Search&code=813920" term="NAICS/611310">
			<label xml:lang="en-US">Standards review committees, professional</label>
			<label xml:lang="es">Normas de los comités de revisión, profesional</label>
			<association type="child-of" reference="http://www.census.gov/cgi-bin/sssd/naics/naicsrch?search=2007%20NAICS%20Search&code=8139"/>
		</category>
		<!-- category, no scheme -->
		<category term="WebStandardsOrg">
			<label xml:lang="en-US">Web Standards Organization</label>
		</category>
		
	</poi>
</pois>

start = element pois { poi* }

poi = element poi {
   id?,
   lang?,
   label+,
   location,
   relation?,
   category*,
   association
}

center = element center {
   system?, latitude, longitude,
}

address = element address {
   attribute country { ISO-3166-ALPHA-3 },
   attribute floor { text },
   attribute language { MARC-ALPHA-3 },
   attribute postalcode { text },
   attribute street { text },
   attribute suite { text }?,
   element region { text }+
}

area = element area { point+ }  # minimum of 3; first and last must be the same.

object = element object { empty } # TBD

undetermined = element undetermined { empty }

relative = element relative {
   attribute location-id { xsd:NCName },
   attribute bearing-to { BEARING },
   attribute distance-from { DISTANCE },
   attribute relative-height { HEIGHT_IN_METERS }?
}

label = element label {
   attribute primary { xsd:boolean }?,
   lang?,
   text
}

route = element route { point+ }


location = element location {
   id?,
   (point | center | address | route | area | undetermined | map | relative)+
}

association = element association {
   attribute reference { xsd:anyURI },
   attribute type { xsd:NCName }
}

relation = element relation {
   id?,
   attribute relative-to { xsd:IDREF },
   attribute type { "contained-within" | "adjacent-to" | "contains" }
}

category = element category {
   attribute source { xsd:anyURI },
   label+
}

point = element point {
   id?,
   attribute altitude { HEIGHT_IN_METERS }?,
   latitude,
   longitude,
   attribute order { xsd:nonNegativeInteger }?
}

# common types
HEIGHT_IN_METERS = xsd:decimal 
DISTANCE = xsd:string { pattern = "[\+]?(\d+(\.\d{1,2})?)(m|km|mi|ft)?" }
BEARING = xsd:decimal { minInclusive="0" maxExclusive="360" }
ISO-3166-ALPHA-3 = xsd:string { pattern = "[A-Z][A-Z][A-Z]" }
MARC-ALPHA-3 = xsd:string { pattern = "[A-Z][A-Z][A-Z]" }
PERCENTAGE = xsd:integer { minInclusive="0" maxInclusive="100" }

# common attributes
id = attribute id { xsd:ID }
lang = attribute xml:lang { xsd:language }
latitude = attribute latitude { xsd:decimal { minInclusive="-90" maxInclusive="90" } }
longitude = attribute longitude { xsd:decimal { minInclusive="-180" maxInclusive="180" } }
system = attribute system { "WGS84" | text }