GIS Integration
GIS Integration associates biodata with locations.
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User Stories
A pest plants team is working on an area on the eastern edge of a reserve. At the same time, another team is doing vegetation monitoring in the western part of the same reserve. A pest animal controller is working on the whole reserve plus a buffer area around it. A plannner has been asked to report on the investment in biodiversity in this reserve, and the outcomes that have been produced. While each aspect of this work relates to a separate area, there is a need for all concerned to know that they are working on the same bit of land.
Checklists
Level One: Data not geospatially referenced.
- Datasets contain no spatial references.
- Data manager is planning GIS integration
Level Two: Data contains some geospatial references.
- Each data set contains a center point reference (coordinates of some description).
Level Three: Data contains standards-compliant geospatial references.
- Each data set contains a polygon description.
- Each polygon description has a date.
Level Four: Data can be accessed as a map layer.
Level Five: Data is available via KML and WMS.
Reference Resources
A Geographic Information System (GIS) is the most common interface to data in local government (according to Garry Tibble of Christchurch City Council).
GIS integrates hardware, software, data, and procedures to facilitate capturing, managing, analyzing, and displaying all forms of geographically referenced information.
Geocoding Data
To prepare your database for GIS analysis, the data needs to have some kind of spatial location assigned to it. This process of assigning co-ordinates is also known as geocoding. At a basic level point data can be recorded, while at a more advanced level vector or shape data can record areas.
- The specific co-ordinate system used is not of great importance as most co-ordinate systems can be translated into each other automatically by GIS systems.
- If a set of co-ordinates for the data is not known, then any kind of spatial information can be used to geocode, including addresses or postal codes.
There are online geocoding tools to convert an address into latitude and longitude co-ordinates, such as Google Maps API Service.
| Address | Return Code | Accuracy | Latitude | Longitude |
|---|---|---|---|---|
| 190 Hereford Street, Christchurch, NZ | 200 | 8 | -43.53216 | 172.640446 |
Accuracy of Location
Data can be captured at a number of different levels of accuracy, from kilometers to centimeters.
- 1m is a simple unit, while 1cm is considered a bigger unit.
- An average $1500 GPS unit can record location with 2-5m accuracy.
- Bigger units will increase the cost of your project
- Other data such as images can captured with accurate spatial information also - digital cameras with GPS units mean that every photo has a GPS location.
Layers of Information
Because data in GIS is geographically located, information from different sources can be linked through this common plane of reference. These datasets can then be arranged into layers that are overlayed to create a single map.
Types of Data
GIS recognises two types of data:
- Spatial data
- Attribute data
Spatial data denotes the absolute and relative location of geographic features and boundaries. These geographic locations are generally labelled using coordinates and topology.
Attribute data details properties of the geographic features and boundaries. This data can be quantitative or qualitative.
These two types of data can be further split into:
- Raster data
- Vector data
Vector data is made up of points, lines and polygons. In this way vector data can mark either the point location of a feature (such as a spring), the trajectory of a feature (such as a river) or the outline of an area (such as a lake).
Raster data divides space into a grid, each cell of which has a discrete value. Data that is typically represented as raster includes terrain elevation data, vegetation inventories, rainfall data, and satellite images.
Benefits
There are distinct advantages to integrating biodata with GIS:
- Increased Efficiency
- Able to filter down changes from one layer of data to another, avoiding the need for multiple manual alterations. For instance, moving a boundary between rural and urban zones in a district on one layer can automatically update the zone designation of the affected property records on a different layer.
- Capable of Powerful Analysis
- Particularly the ability to correlate previously unconnected datasets.
- Can correlate data easily
- See separate layers of data
- Query separate datasets using simple or sophisticated criteria
- Can ask specific questions
- Such as, 'what is/are the habitat(s) of organism x?'
- Can solve routine queries
- Such as, possible impacts of resource consents
- Greater Capacity to Share Data
- If Biodata is geocoded (given a spatial value) it is more meaningful and accurate when shared with other systems or people.
Potential Issues
The three main issues with making biodata GIS-capable are quality data capture, applying relevancy to data, and metadata standards.
Resources
For more information and resources about geospatial data and practice in New Zealand, see the New Zealand Geospatial Strategy website. The site includes an index of New Zealand geospatial data as well as some biodata-related case studies. GIS.org.nz also contains a GIS wiki.
A paper and presentation given at the 2nd GIS Summit by Dr Greg Partington, from Lenex Pty Ltd Australia, regarding applications for spatial data modelling, are available below:
Greg Partington Paper 9 June 2009
Greg Partington 2nd GIS Summit Presentation
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