NZ Topo - object class canal_poly

This page describe the canal_poly object class used to represent objects in the NZTopo topographic database.


An artificial open waterway used for transportation, waterpower or irrigation.

Topo50 description

Canal_poly is used to capture canals where they are large enough to hold at 1:50,000 as an area feature. Narrower canals are captured as a centreline. Where a canal is close to a road, the position held in the data is as close to it's true position as capture techniques permit. This may result in part of the canal feature being obscurred by the road symbol. Other objects completing the water-flow pattern are: river, lake, swamp, water race,pond, lagoon and pipeline_cl (where pipeline_use = 'water)

Representation specification

Representation specification showing canal_poly

Click to enlarge image

See also: siphon_poly canal_cl

Class attributes

Attribute Value
Object class canal_poly
Entity class WATERCOURSE
Additional entity class Not applicable
Object inheritance simple_area
Entity source US Standard Entity
Map series Topo50 Topo250
LSLIFF object class 303

Object attributes

Attribute LSLIFF code
Shapefile field
Data type
Attribute description Attribute values*
name 1001
Name of the canal, where known. Text data from July 2012 will be in UTF-8 format. If your system is not UTF-8 compliant, you will need to use the name_ascii attribute, which has had any macronated vowels removed. UTF-8 stands for Unicode Transformation Format-8. It is an octet (8-bit) lossless encoding of Unicode characters. UTF-8 encodes each Unicode character as a variable number of 1 to 4 octets, where the number of octets depends on the integer value assigned to the Unicode character. It is an efficient encoding of Unicode documents that use mostly US-ASCII characters because it represents each character in the range U+0000 through U+007F as a single octet. UTF-8 is the default encoding for XML.
"Oakden Canal"
name_macronated 1140
Indicates whether the entry in the name_ascii field contains a macronated vowel. Where the value is "Y" go to for a list of places or feature names within New Zealand that are gazetted and include macrons
name_ascii 9000
Text data from July 2012 will be in UTF-8 format. If your system is not UTF-8 compliant, you will need to use this attribute, which has had any macronated vowels removed.
UFID 1000
A unique identifier for use on Topo50 data in the LINZ Data Service. This is not a universal ID. The intention is to manage these ID’s as persistent, however this is not guaranteed and there will be instances where what appears to be a minor change to a feature may result in a new ID being assigned.

* See explanation of attribute values for more information about how attribute values are represented.

Change log

Feature version Revised Description
9 2014-11-14 Updated definition
8 2012-08-28 Updated map image and aerial view; added representation specification and example feature photographs
7 2012-08-28 Added scale-specific definitions
6 2012-08-28 Added scale-specific definitions
5 2012-08-16 Name attribute in UTF-8 format; added name_ascii attribute
4 2010-03-01 Added name_macronated attribute
3 2008-04-10 Removed reference to seed and void objects
2 2001-11-23 Unspecified update
1 1999-03-01 intial status