1.3. Glossary

cell:
A single, usually rectangular element in a termraster model. A cell stores a single numeric value and has a termresolution defining its size 'on the ground'.
chi statistic:
A measure of the difference between the observed and expected counts of a phenomenon based on some underlying assumption about the expectation.
choropleth:
A choropleth map uses coloured area symbols to represent the statistical and spatial variation in a measured phenomenon. The representation is continuous (area filling) but abrupt. Whilst data are frequently collected, or at least distributed, using area aggregations a number significant issues mean that although they represent the underlying data model accurately and are easy to produce using modern computers, choropleth maps are not particularly effective graphical representations of many of the phenomena that they are used to show (Dykes et al. 1998).
colorBrewer:
Online software designed to provide plausible colour schemes to use in a range of environments when mapping phenomena that vary in a number of different ways (Brewer 2002). Cindy Brewer refers to ColorBrewer as "a color diagnostic tool" through which users can "'test drive' a given color scheme to see if it suits your mapping needs".
DEM:
Digital Elevation Model. A raster representation of part of the shape of the earth's surface. Each cell in the raster represents a single elevation value.
download:
To complete this tutorial you will need to 'download' various pieces of software and data files that we are making available online through our 'download' page. You will find complete listings of all resources required here :
eLML:
eLML is the e-Lesson Markup Language, as used here to produce these materials
Flickr:
Flickr is an online photo management and sharing application to help people organise photographs in new ways and make them accessible to others. It contains an Applications Programming Interface through which the photographs and information about them can be accessed : http://www.flickr.com/about/
geobrowser:
Software that provides access to rich spatial data sets and sophisticated and intuitive interfaces through which they may be explored. Many use open, well documented data formats and contain applications programming interfaces that allow 'mashups' of data from different sources to be developed. NASA WorldWind, Microsoft Virtual Earth and termGoogle Earth are examples.
GI science:
Geographic Information Science. The science that develops methods for modeling spatial phenomena and provides analytical approaches to handling geographic information.
GI system:
Geographic Information System (GIS). Software that draws upon Geographic Information Science to store and process geographic information in meaningful and useful ways.
GML:
the Geographic Markup Language (GML) - an termXML grammar defined by the "Open Geospatial Consortium" (Open Geospatial Consortium 2008) to describe spatial features and phenomena that adheres to published standards. It is used for distributing geographic information by a number of national mapping agencies - including the Ordnance Survey in their MasterMap product.
GoogleEarth:
Google Earth (Google Inc. 2008) is one of a number of 'termgeobrowsers ' that provide access to georeferenced information through a global interface. Google Earth is particularly popular due to the huge amount of georeferenced aerial photography that is available through the application, the sophisticated interface and seamless integration with Google's other spatial services. Anyone can publish spatial information in Google Earth using termKML .
GPX:
GPX is the GPS exchange format that has become a de-facto Web standard for exchanging GPS tracks, routes and waypoints.
KML:
KML is the Keyhole Markup Language - an termXML dialect developed to describe spatial features and phenomena for use with termGoogle Earth and Google Maps.
LandScript:
The scripting language used by termLandSerf for performing repeated processing tasks. It is based upon 'map algebra' through which rasters are processed with concise functional descriptions. Documentation for LandScript is available from the LandSerf web pages (Wood 2008).
LandSerf:
A free GI System for the handling spatial data. It is designed primarily for processing surface data, but can be used to manipulate and generate most common raster and vector data formats.
Panoramio:
Panoramio is an online photo management and sharing application that uses termGoogle Earth and Google Maps to georeference and display photographs. It is designed to "help to link photos and places". The content is available through termGoogle Earth in the 'Layers' window : http://www.panoramio.com/
PHP:
PHP is an application that runs on a server. It contains a scripting language through which commands can be issued on servers before information is sent to a client. This means that particular responses can be made to particular requests for information. Frequently PHP is used to process the text contained in the URLs that are sent in requests to servers and to generate document content 'on-the-fly' when particular URLs are requested. PHP scripts are often used to interrogate databases on Web servers and to provide documents that contain the results. For example, an HTML document that contains information relating to a particular person or product, or a KML document that contains the results of a spatial query.
raster:
A regular grid of numbers representing a usually continuous portion of space. Unlike a bitmapped image, geographic rasters can represent measurements or counts in addition to colour.
resolution:
The dimensions, measured in spatial units of a termraster termcell (e.g. 1 arc-second, or 30m). The larger the number, the less detail is represented by the raster. Many rasters have a common resolution in an x- and y- direction resulting in square raster cells, but this is not a requirement of most raster models.
text editor:
We recommend using a text editor that colours text when editing KML files so that elements, attributes and marked-up content are clearly differentiated. Examples include TextEdit, CoffeeCup and EditPlus. Some of these editors have sophisticated 'search and replace' functionality and are designed for managing large collections of text documents.
valid:
termXML files that are valid comply with the rules and syntax of the particular language or dialect to which they comply. termXML files of any dialect that are not valid will not be interpreted correctly by the applications that use them. All termXML files should be valid and termwell-formed .
vector:
In the context of termGI Science , a vector or vector map is a representation of (a) spatial object(s) using simple geometry to define object boundaries. Objects can be points, lines, polygons or volumes.
well-formed:
termXML files that are well-formed contain :termXML files of any dialect that are not valid will not be interpreted correctly by the applications that use them. All termXML files should be well-formed and termvalid .
XML:

The eXtensible Mark-up Language, XML allows us to use text to define entities and specify hierarchical relationships between them. An XML language contains elements that represent entities. Elements are coded using a standard convention :

<elementName>text describing element</elementName>

Additionally, attributes can be associated with elements - these are defined within the opening tags of elements:

<elementName attributeName="attributeValue">text describing element</elementName>.

Each XML language or dialect is defined by the users of the language in a single definition file or schema that defines the various elements and attributes and the relationships between them that are allowed. Examples include termKML , termGML , termGPX and termeLML .

Update: 14th October 2008 (eLML) - Contact - Print (PDF) - ©