9.2 LINZ Bathymetric and nautical charts databases

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Database Title	9.2 LINZ Bathymetric and nautical charts databases
Keywords Type1. Type 11.	New Zealand EEZ; coastal marine; bathymetry
Abstract	This consists of 4 datsets: General Bathymetric Charts of the Ocean (GEBCO) Coastal Nautical Charts for New Zealand coastal waters Bathymetric chart and coastal nautical chart source data. Hydrographic Information Tracking System (HITS). This is electronic metadata about the data that is used in compiling nautical charts.
Geographical Coverage	Includes coastal waters; EEZ and seas well beyond the EEZ (see NZ 202-Chart Catalogue).
Dataset start date.	mid 1800's
Dataset end date.	Current
Status/currency.	In progress
Update frequency.	As new surveys are undertaken.
Maintenance.	1. International Hydrographic Organisation, Boulder, Colorado with new material now being sent from NZ digitally. 2-4. LINZ - as new surveys are undertaken.

Technical Evaluation
Parameters- what is measured	Depth at position. Depth at position, tidal streams and currents, heights of objects, navigation marks, composition of seabed (in selected locations). Soundings, positions including the coastline and drying line, heights of objects and landmarks; tidal heights, tidal streams and currents, eddies and overfalls, composition of the seabed, navigation marks. For each chart/part chart: age of data; who did the survey; scale; type of data (eg. authoritative survey sheet, historic survey or chart); ship that carried out the survey; type of media the data stored is on and the condition of the data.
Parameters- what is calculated	3. Sounding reductions (corrections for tidal height , survey vessel characteristics etc)
Methods used to measure parameters	Scientific ships collect data. Hydrographic surveys by accredited providers under contract to LINZ following the procedures in the LINZ Standards for Hydrographic Surveys (latest version v.2.0 (10 Jan 2000). A new section on digital data formats for hydrographic soundings was issued on 6 March 2000). Survey records are stored by chart as paper records (and microfiche copies). Digital database
Scale of use.	1:1,000,000 1:200,000-300,000 with more detail in specific areas eg. harbours/ habour approaches. 1:100,000-1:10,000 (harbours).
Number of records	Many
GIS compatibility.	new data digital. Programme to digitise all GEBCO data. analogue data analogue data Paper charts are being scanned to produce raster nautical charts using Seafarer (an Australian Navy product). The product will be available on CD ROM. Users pay for access to specified charts. The next step is the production of S57 Electronic Nautical Charts for use in Electronic Chart Display Information Systems. These charts have the soundings and tidal data as vectors which means that the data can be manipulated (eg to produce a digital terrain model, adjusting soundings for time of viewing (ie adjusts for tide))
Available formats for users.	paper charts paper charts; raster charts(by end 2000) paper records and microfiche MS Access database
Access constraints.	1&2. Available from nautical retail outlets for a fee ($20/chart approx) 3. Available on request 4. Available at LINZ
Measurement Accuracy	To be completed by database manager.
Completeness of dataset	To be completed by database manager.
Positional accuracy	To be completed by database manager.
Database steward	LINZ
Database custodian	LINZ
Database custodian contact person	Mike Farrell
Database custodian Contact Address Phone Fax Email	National Topographic/Hydrographic Authority Private Box 5501 Wellington +64 4 460 0560 +64 4 471 6894 mfarrell@linz.govt.nz
References	Land Information New Zealand. Standards for Hydrographic Surveys (HYSPEC) v2.0. TH Standard 31. 10 January 2000. LINZ Hydrographic Survey Digital Data Formats. TH Standard 33. 6 March 2000.
Date metadata record prepared.	June 2000
Author of metadata record.	Victoria Froude

Management Evaluation
Original purpose.	To provide nautical charts for mariners
Relationships with classification systems.	N/A
Relationships with other databases	Tidal datasets are used in compiling some charts.
Known relationships with proposed EPIP indicators.	Not known.
Database uses?	1&2 (paper charts) are used extensively by mariners, commercial users. The raster charts will be used by a subset of mariners, commercial users and researchers. 3&4 are used by LINZ and specialised users.
Public awareness of the database	1&2- high for mariners. 3 & 4-relatively low
Database strengths.	Good coverage The charts (1&2) have been compiled using more detailed scale data. This more detailed information (3) is available for more detailed interpretation. Current surveys are done to a consistent high standard specified by LINZ. This includes details on addressing accuracy of measurements. New surveys (post May 2000) are to meet standards for digital data formats
Database limitations.	Soundings data is not digitised as S57 compliant Electronic Nautical Charts (ENCs)(other than for 4 trial charts currently being prepared). The raster data (Seafarer) can not be queried in contrast to the vector data (digitised s57 compliant ENCs). No active plan to digitise remaining existing charts (1&2) as this requires extra funds. As there are only 3 new surveys per year it will take many years to achieve digital coverage this way.

What are the Current and Emerging Uses of the Database for:
Assisting with determining historic state/baseline.	Could do this using old information where this is available.
Assisting with determining current state/baseline.	1-3 are used directly for this. New surveys are done to higher levels of accuracy than earlier surveys.
Assisting with modeling possible future outcomes.	Digital data which is now being collected (as at May 2000) will enable the construction of seabed digital terrain models.
Risk assessment.	1-3 identify shallow locations where there is a risk of grounding; and bottom sediment where there may be inadequate holding. This allows mariners to make judgements about appropriate routes of passage (former situation) and suitable anchoring locations (latter situation).
Monitoring site selection and sample design.	1-3 could be used to stratify sampling based on depth or tidal currents.
Aggregating and reporting data locally, regionally or nationally.	N/A