Landbase Data
Terralink International Landbase data is designed for use as an intelligent digital map within Geographical Information Systems (GIS) and database systems. The purpose of Landbase data is to support a wide range of customer applications that utilise geographical information. These may include:
- Geographical analysis
- Geographical referencing
- Data association
- Asset management
- Route planning
- Cartographic representation
Each feature has a spatial attribute that is either a topological relationship to another feature that defines its spatial context, or a geometric representation such as a point, line or polygon.
Road and Rail Networks
Landbase road features are a representation of the physical road and named or numbered roads. These road features include the road classification and:
- road centrelines, physical and unformed legal roads
- road attributes such as classification, surface type, number of lanes, lane flow, speed limits
- road centreline structures, bridges, tunnels and fords
- road names and alternative road names
- road intersections, controls, roundabouts and turn restrictions at intersections
- kerbs
- railways
The Landbase road routing features provide information that compliments the road network. These include detail that may affect a driver’s choice of route, such as mandatory turns or one-way streets.
Topographic Features
Landbase topographic features are representations of real-world objects such as buildings, roads, tracks, paths, railways, rivers, lakes, ponds, and structures.
Also:
- physical property boundaries
- parks and reserves boundaries
- hydrography; lakes, coastline and rivers
- map sheet extents
- structures such as oil storage tanks and pylons
Address data
Terralink International Landbase has a wealth of addressing information that is regularly used for locating and geocoding client information. Addresses include legal and alias addresses as well as address ranges, ensuring accuracy in the application of addressing information
The data sets include:
- address points
- address ranges on road segments
- post codes
- place names
- town extents and names
- Police suburbs
- Territorial Local Authority boundaries
- mesh block and area unit data
Imagery
The Landbase imagery layer is not part of the feature model but provides a seamless source of ortho-rectified aerial photography that is recommended for use with Landbase features. Terralink has the most extensive and current coverage of New Zealand aerial imagery available and is completing it’s National Imagery Acquisition Program that will result in Terralink having seamless coverage over 100% of New Zealand within 3 years.
Imagery is converted to Mr SID format and geo-referenced. The Mr SID format means there is minimal lost of image resolution and file sizes are typically 1/10 the size of the equivalent quality TIFF file. Using Smallworld Imagery system, a seamless catalogue of images can be presented to the user.
Orthophotography is captured either in terms of NZMG or NZTM projection. Pixel resolution depending on nominal scale ranges from 2.5m GSD (1:25,000) to 12.5cm GSD (1:500).
Complementary data
The Landbase layers can be complemented with data from other databases within Terralink International such as;
- legal property data
- raster 1:50,000 topographic maps, geo-referenced
- raster orthophotography at different scales, geo-referenced
- raster street maps
- 1:50,000 topographic vector data
- Land Cover Database
- cartographic street map design files
Client data can be incorporated on separate layers, or can be linked into existing data matching items such as street address, land appellation or title reference. Other publicly sourced data can be linked in, such as Statistics NZ data.
Terralink International has automated tools for receiving data from many sources, including spatial data in ESRI shape, MapInfo MID/MIF, Microstation DGN, Laser-Scan IFF; and aspatial data in CSV, or tab-delimited format. The received data goes through QA processes to ensure it is suitable for inclusion in Terralink International’s system. Our maintenance engine systems include many automated techniques for assigning address to roads, address range maintenance, road name maintenance and so on.
Data Formats
With technology and data being core to Terralink International, we have consequently well developed processes for supplying data to client requirements. The Landbase publishing database is neutral Oracle Spatial – i.e. it doesn’t belong to any one GIS vendor. Terralink International also has automated tools to supply in all popular GIS formats, including ESRI Shape, MapInfo MID/MIF, Microstation DGN, Laser-scan IFF, etc.
Data goes through a rigorous Quality Assurance process to assure its integrity. Metadata and statistics about each feature can be supplied with data delivery. Additional client requirements can be met e.g. supply data in a particular client-specified region; supply a subset of tables or attributes.
Terralink International Landbase national data sets include:
- Road centrelines
- Road attributes such as classification, surface type, number of lanes, lane flow, speed limits
- Road structures – bridges, tunnels and fords
- Road names
- Road Intersections and restrictions
- Kerb lines
- Address points
- Address ranges on road segments
- Physical property boundaries
- Parks and reserves boundaries
- Hydrography, lakes, coastline, etc
- Local Authority boundaries
- Mesh Blocks
- Railways
- Map Sheet extents
- Post Codes
- Place names
- Town extents and names
- Suburbs