Location Analysis & GIS

Offering advanced location analysis and integrated Geographic Information Services (GIS) to help you better understand and describe your wireless operating environments.

Contact us to discuss integrating Key Bridge technologies into your own solutions.

Integrated and Interoperable


Digital elevation data rendered with shadowing and photograph overlay

Key Bridge Location Services are built upon an integrated and interoperable set of component technologies for geographic analysis and calculation. Location Services are designed and developed for low-latency, high-reliability, predictable precision and seamless interoperability.

Service components can be accessed independently or together in any combination you require to create sophisticated analysis engines that exactly match your needs. Transactions use the Wireless Service Information Format, a standard and open common object model, which simplifies and shortens your development time and ensures robust data integrity and predictability.

Standards, Specifications & References

Key Bridge services support and can read and write geometry information formatted according to the following specifications:

The WSIF Specification

The Key Bridge Geographic Analysis Engine conducts all transactions suing the WSIF open data model. A solid understanding of the geometry model described by the Simple Feature Access is also helpful.

This open, public data model that can describe any type of wireless service including unlicensed White Space networks and devices.


Digital Elevation

Global digital elevation coverage & availability

Key Bridge offers convenient programmatic access to digital elevation and altitude data for locations world wide.

A digital elevation model is a digital model or 3D representation of the planet's surface created from terrain elevation data. The quality of an elevation model is a measure of how accurate elevation is at each pixel (absolute accuracy), sampling density, grid resolution (e.g. pixel size) and vertical resolution.

Different elevation models incorporate higher quality coverage for different areas, typically corresponding to national political boundaries.

Key Bridge maintains and provides convenient access through a common interface to a number of different elevation models. You may dynamically select and work with digital terrain models based upon your desired geographic location, the model's coverage area, and your required the degree of precision.

Spatial resolutions are available with 30, 15, and 7.5 second global coverage and with country and area-specific resolutions increasing up to 1/9 arc-second (about 3 meters) samples where available..

Available Models

A digital terrain models represents the bare ground surface without any objects like plants and buildings. We also offer coverage and clutter data. Currently supported models include:

  • Global Multi-resolution Terrain Elevation Data 2010 (GLOBE) 30 seconds of arc
  • Shuttle Radar Topography Mission (SRTM) 1 & 3 seconds of arc
  • National Elevation Dataset (NED) 1/9, 1/3, 1, and 2 seconds of arc
  • Canadian GeoBase Initiative (CDED)

Custom Formats

Contact us if you require coverage of a specific operating area at a resolution or with data model not currently supported. In most cases we can develop, test and implement a new data model that exactly suits your needs in a matter of weeks.

Geographic Analysis Engine

The Key Bridge Geographic Analysis Engine provides standards compliant methods for the manipulation of geospatial data.

The Geographic Analysis Engine is built upon a mathematically robust set of core libraries and data structures defined by the Open Geospatial Consortium (OGC). The Engine delivers high-throughput and high-availability calculations across a wide variety algorithms and input data. It is a core component of the Key Bridge White space system and a number of other projects, including commercial web services and desktop applications.

Operations may be implemented in any coordinate reference system and include calculating the orthrodromic distance between two points, creating a regular or irregular buffer around a point or extended geometry, determining true heading angle between two points, identifying the geographic centroid of an extended area, coverage area and orthrodomic distance along a path, among others.

All operations are mathematically robust and invertible. Standard geodetic datums are supported including NAD27, NAD83 and WGS84 and all EPSG projections. Flat and non-standard projections are also supported.

Set-Theory Spatial Analysis

Set-theory spatial analysis methods

Geometric Set Analysis forms the foundation of most geographic information systems, and the Key Bridge Geographic Analysis Engine supports spatial set analysis methods including intersection, union, difference and symmetric difference on all defined Geometry classes including Point, LineString, Polygon and their Multi- variants.

Positive and Negative Buffering

Positive and negative geometric buffer operations

Another commonly accessed analysis method is the buffering, both positive and negative, of a geographic feature. This capability enables simplified proximity and area-based coverage analysis and, when combines with Set analysis methods, is a powerful tool for determining location-based inclusion and exclusion.

The Key Bridge Geographic Analysis Engine enables uniform and predictable buffering operations in any map projection and at any latitude.

Simple Feature Access

Simple feature access (SFA; also called ISO 19125), is both an OpenGIS and ISO Standard that specifies a common storage model of geographical data (point, line, polygon, multi-point, multi-line, etc.) using well-known text (or binary).

The default geometric coding employed by all Key Bridge services is defined in the Wireless Service Information Format (WSIF) and relies upon a subset of classes defined in the Simple Feature Access (SFA) Geometry model. These are: Point, MultiPoint, Polygon, MultiPolygon, LineString and MultiLineString, which are themselves implementations of the SFA Geometry object interface and, by definition, may include a SFA SpatialReferenceSystem and a SFA MeasureReferenceSystem.

Geometry class hierarchy showing the class relationships

In the WSIF specification only a SpatialReferenceSystem is allowed, which is used to identify and persist the geodetic datum. Any MeasureReferenceSystem should be ignored.

Standard geometry types

The most commonly encountered geometry object a Point, with extended areas (e.g. buildings, facilities and contours) represented as Polygons and MultiPolygons.

The SFA Polygon

A Polygon is a planar Surface defined by 1 exterior boundary (defined by a closed LinearRing) and 0 or more interior boundaries (also defined by one or more closed LinearRings). Each interior boundary defines a hole in the Polygon. The exterior boundary LinearRing defines the “top” of the surface as is the side of the surface from which the exterior boundary appears to traverse the boundary in a counter clockwise direction (e.g. following the right-hand-rule).

Interior LinearRings will have the opposite orientation, and appear as clockwise when viewed from the “top”. The rules that define valid Polygons are as follows:

  • a) Polygons are topologically closed (i.e. the exterior boundary is by a closed LinearRing);
  • b) The boundary of a Polygon consists of a set of LinearRings that make up its exterior and interior boundaries;
  • c) No two Rings in the boundary cross; boundary Rings may intersect at a Point but only as a tangent
  • d) A Polygon may not have cut lines, spikes or punctures
  • e) The interior of every Polygon is a connected point set;
  • f) The exterior of a Polygon with 1 or more holes is not connected; that is, each hole defines a connected component of the exterior.

The combination of (a) and (c) makes a Polygon a regular closed Point set and a simple geometric objects.

The SFA MultiPolygon

A MultiPolygon is a MultiSurface whose elements are Polygons. The assertions for MultiPolygons are:

  • a) The interiors of 2 Polygons that are elements of a MultiPolygon may not intersect.
  • b) The boundaries of any 2 Polygons that are elements of a MultiPolygon may not “cross” and may touch at only a finite number of Points.
  • c) A MultiPolygon is defined as topologically closed.
  • d) A MultiPolygon may not have cut lines, spikes or punctures; a MultiPolygon is a regular closed Point set:
  • e) The interior of a MultiPolygon with more than 1 Polygon is not connected; the number of connected components of the interior of a MultiPolygon is equal to the number of Polygons in the MultiPolygon.

The boundary of a MultiPolygon is a set of closed Curves (LineStrings) corresponding to the boundaries of its element Polygons. Each Curve in the boundary of the MultiPolygon is in the boundary of exactly 1 element Polygon, and every Curve in the boundary of an element Polygon is in the boundary of the MultiPolygon.


Material in this section is reproduced from the OpenGIS® Implementation Standard for Geographic information - Simple feature access - Part 1: Common architecture with footnotes provided for clarification. All material in this section is Copyright © 2010 Open Geospatial Consortium, Inc. and is provided here for convenience.