Title

Vicmap Hydro - Water Poygon Fuzzy 

Alternate title

HY_WATER_AREA_FUZZY 

Purpose

The HY_WATER_AREA_FUZZY table holds the more indicative natural Hydrographic features within Vicmap Hydro. Vicmap Hydro provides an accurate representation of natural and man made Hydrographic features across Victoria, at a capture scale of 1:25,000. It is used in a variety of applications, particularly in emergency services, natural resource management, planning and development, and digital map publication. 

Credit

Project Instigator: George Mifsud Data Capture: Lisa Cheong Data updates: Samuel Hislop, Kathryn Germain, Richard Stewart 

Supplemental Information

Related Documents: None Please see Vicmap Features of Interest product description for more detailed information on this product. This can be found on the Vicmap Features of Interest webpage. http://www.delwp.vic.gov.au/vicmap > Vicmap Products > Vicmap Features of Interest http://www.delwp.vic.gov.au/vicmap 

Status

Completed  

Horizontal Accuracy

25m  

Code

4283 

Maintenance and update frequency

As needed  

Topic category

• Inland waters

Use limitation

. To be used for labelling only. Not to be used for GIS analaysis, spatial modelling or area statements 

Classification

Unclassified  

Statement

Dataset Source: Geographic Areas Hydro Label is sourced from the original published 1:25 000 topographic maps sheets produced from 1975 to 1995. An additional source was the Geographic names Register. As part of the conversion to digital data process in the 1990s, each 1:25 000 map sheet was scanned. The relief and hydrographic area map textual information was incorporated as annotation as part of the SDMB-T (State Digital Map Base - Topographic) layers MORPTH25 and SHORE25 respectively. Note that this information was created specifically for use at 1:25 000 and was dependent on the 1:25 000 index system There is no Vicmap dataset that contains spatial information depicting geographic areas. So to display this information for Vicmap Topographic purposes the SDMB_T annotation layers were used. This posed some limitations in its use. For instance the annotation for the text 'PORT PHILLIP BAY" was created over the extent of the feature for every single format 1:25 000 map where the feature occurred. Hence over a Vicmap Topographic 1:25 000 mapsheet, which is two single format sheets side by side, this textual information would potentially be displayed twice. This same annotation may be truncated on the edges of Vicmap Topographic 1:30 000 A4 map sheets (see fig 1.) On the Vicmap Topographic 1:50 000 map sheets the annotation may not be readable due to its reduced size, and may appear several times in the map area. Dataset Originality: Primary & Derived 

Description

Collection Method: Screen digitized using coastline and SHORE25 

Description

Hydrographic areas were identified on compilation maps displaying SHORE25 annotation. Individual polygons were then screen digitized for each appropriate annotated feature. The name, feature type code, land type and level properties were populated for each new polygon. The boundary was determined by the coastline on the landward side and a concave arc out to sea on the seaward side intersecting with the coast at a logical point, usually at the tip of a headland. For mapping and display purposes each polygon would be labelled with the name of the feature. The boundary line would not shown. 

Classification

Unclassified  

Attribute Quality

Comments

90% 

Positional Accuracy

Comments

Not valid due to fuzzy nature of polygons 

Conceptual Consistency

Comments

Due to the nature of the data, this data set may contain: overlapping polygons intersecting linework polygons with no labels 

Missing Data

Comments

State Wide Completeness Verification: State wide QA process 

Excess Data

Comments

80% classification accuracy