Geographical Information System (GIS) Flashcards
what is gis?
a collection of computer hardware, software, data, people and processes designed to capture, store, update manipulate, analyse and display spatially referenced data
components of GIS
- hardware
- software
- data
- people processes
functional element of GIS
capture, store, update, manipulate and analyse spatially referenced data
two types of data in GIS
- spatial data
- attribute data
spatial data
the shape and location of geographical features
attribute data
the characteristics of geographic features
two methods of storing data in GIS
- vector data
- rasta data
vector data
the representation of an area using points, lines and polygons
rasta data
the representation of an area using grid cells or pixels
processes when working with GIS
- data input
- data storage
- data analysis
- output information
- data mangement
- data application
sources of information for GIS
- remote sensing
- survey data
- measure data
- primary data
- secondary data
remote sensing
aerial photos and satellite images
survey data
roads, railways, altitude census data
measure data
e.g. rainfall, temperature, air pressure etc.
primary data
first hand observations and measurement
secondary data
existing data measured and captured by another organisation
how can GIS be used to assist with the location of a business?
- find information about other existing businesses
- determine demand for business
- find ideal location for business
- work out routes for deliveries
what is remote sensing?
the observation of the earth from a distance through satellites or aeroplanes
what is remote sensing used for?
to study landscapes, ecosystems, hydrology, atmosphere, climatic change, human development and the impact of humans on the environment
types of remote sensing
- passive sensors
- active sensors
passive sensors
sensors that measure reflected sunlight emitted from the sun
active sensors
sensors that send light to their targets and measure the reflected energy back to them
advantages of remote sensing
- data can be collected for inaccessible areas
- large areas can be captured as images
- they can be delivered quickly
what is a data base?
a collection of data organised for use in computers
what is data layering / thematic?
the placing of one map on top of another to see the relationship between different sets of data
uses of layering / thematic
- different sets of data can be compared
- relationships between different sets of data can be established
- analysing different sets of information
- comparison can assist with future developments
what is data integration?
the integration of data from different maps into one map which summaries the overlaying process
problems experienced with data integration prior to the introduction of GIS
- maps have different scale
- different map projections are used on maps
- different geo-referenced maps are used
why is data integration important to a geographer?
a summary of integrated data is produced which makes it easier to analyse data
what is buffering?
a process of demarcating an area around a feature
what is data manipulation?
when data is processed and converted into useful information
why is it necessary to manipulate data in a database?
- correct distortions
- sharpen definition
- ensure colour consistency
- correct latitude and longitude registration
- makes data more manageable
what is statistical analysis?
interpreting the various forms of statistics in relation to a query
what is data standardisation?
making the data similar to other data sets to allow data sharing
what is querying ?
investigating the data and finding answers about specific parts of the dataset
what is data sharing?
making the data available for other users to access
what is data security?
ensuring that data is safe from tampering and not everyone has access to sensitive data
what is data back up (backing up data)?
recovering data — important part of data security
what is resolution?
the detail and clarity of images in satellite and ariel photographs
- the smaller the pixels, the clearer the image
what is spatial resolution?
the detail with which a map shows the location and shape of geographic features
ways in which GIS can be used to assist a farmer before consider cultivation
- availability of water
- fertility of soil
- relief of the land
- micromlimate
- access to infrastructure
- access to transport
