ANZLIC Identitifer ANZCW1202000173 Title Australian Irrigation Areas, Version 1a, National Land and Water Resources Audit Custodian Bureau of Rural Sciences Jurisdiction Australia Description Abstract This data set shows designated and actual irrigation areas in Australia compiled by the National Land Use Mapping Project of the National Land and Water Resources Audit to assist in the identification of irrigation areas in Australia. Additional data custodians include Agriculture WA, Queensland Department of Natural Resources and Mines, Murray-Darling Basin Commission, New South Wales Department of Land and Water Conservation and Tasmanian Department of Primary Industries, Water and Environment. "Designated irrigation areas" indicate areas with administratively defined boundaries which have associated rights and obligations pertaining to use of water for irrigation. The precise meaning of the term "designated irrigation area" varies from region to region. "Actual irrigation areas" indicate areas with observationally defined boundaries within which irrigation is practised. The boundaries have been supplied by various agencies and cover the more important irrigation areas in Australia. Users of this data set should be aware that there are irrigated areas outside the designated and actual areas shown and that there are non-irrigated areas inside them. This is particularly true of Tasmania and the Murray-Darling Basin. The data set is available in both vector and raster formats. The raster data set can be used as a companion to the 1996/97 Land Use of Australia data set which is also in raster format. Both data sets have the same coordinate system, boundary coordinates and cell size so that they can easily be overlaid. Users may find, however, that some cells are classified as irrigated by the Australian Irrigation Areas data set and as non-agricultural land by the 1996/97 Land Use of Australia data set. The Version 1a data set may be of use to researchers and policy makers in need of national, regional or local scale irrigation data, though the scale of the source material is highly variable and completeness of coverage is poor in some regions. Search Words AGRICULTURE AGRICULTURE Irrigation BOUNDARIES BOUNDARIES Administrative BOUNDARIES Cultural LAND LAND Use LAND Management Geographic Extent 112.5050 -44.0050, 154.0050 -44.0050, 154.0050 -9.9950, 112.5050 -9.9950 Data Currency 1996-1997 Ending Date Not Known Data Set Status Status Complete Maintenance and Update Frequency Not Planned Access Stored Data Set Format DIGITAL ARC/INFO 7.2.1 under SunOS Available Format Types DIGITAL - ARC/INFO raster DIGITAL - ARC/INFO vector Access Constraint Data are available subject to a Commonwealth licence agreement. Data compiled from sources to be acknowledged in any published material as: "Australian Irrigation Areas Version 1a, National Land and Water Resources Audit. Compiled by Bureau of Rural Sciences from data supplied by Agriculture WA, Queensland Department of Natural Resources and Mines, Murray-Darling Basin Commission, NSW Department of Land and Water Conservation and Tasmanian Department of Primary Industries, Water and Environment" Data Quality Lineage The data set was constructed in vector format by appending irrigation area boundary data sets supplied by various agencies. The component data sets are listed below. One of the component data sets which was supplied as separate tiles in ArcView shapefile format was assembled into a single shapefile data set in ArcView 3.1. All other processing was carried out in ARC/INFO 7.2.1 under SunOS using double precision coordinates. For all operations in which processing used a fuzzy tolerance, the value specified was 0.00001 degrees (about 1 m). The raster form of the data set was made from the vector form. 1) Ord River Scheme, Stage 1, irrigation area boundaries. This data set was supplied by Agriculture WA in ArcView shapefile format. 2) Boundary of Gazetted Irrigation Areas in Queensland. This data set was supplied by the Queensland Department of Natural Resources and Mines in ARC/INFO export file format. It shows designated irrigation areas. The coordinate datum is not known with certainty and was assumed to be the Australian Geodetic Datum 1984. 3) Northern Murray-Darling Basin irrigation area boundaries. This data set was supplied by the Murray-Darling Basin Commission in ARC/INFO export file format. It shows actual irrigation areas, based on interpretation of coarse scale imagery derived from Landsat TM images. The data set comprises 11 polygons. Of these, five have not been retained in the national data set because they largely coincide with the much higher resolution polygons of the Northern New South Wales Cotton Development data set. A sixth has not been retained because it proves to be almost entirely covered by a national park and a perennial lake. One of the polygons that was retained was edited to give precedence to a higher resolution polygon in the Boundary of Gazetted Irrigation Areas in Queensland data set which it partly overlies. 4) Northern New South Wales Cotton Development data set. This data set was supplied by the New South Wales Department of Land and Water Conservation, in ArcView shapefile format, as 50 separate tiles. It shows actual irrigation areas and a variety of other land uses and land covers related to cotton growing. It is based on interpretation of aerial photography and satellite imagery with extensive field checking. Only the polygons showing irrigation areas were included in the national data set. The tiles were merged in ArcView using the merge function of the GeoProcessing Wizard. Further processing was undertaken in ARC/INFO. 5) Southern Murray-Darling Basin irrigation area boundaries. This data set was supplied by the Murray-Darling Basin Commission in ARC/INFO export file format. It shows designated irrigation areas. It is a compilation of data sets supplied to the Murray-Darling Basin Commission by various contributing agencies through coordinating agencies in each of the three states concerned. The contributing agencies were: New South Wales Murray Irrigation Victoria Goulburn-Murray Water Wimmera Mallee Water Sunraysia Rural Water South Australia SA Water Central Irrigation Trust Renmark Irrigation Trust The state coordinating agencies were: New South Wales Department of Land and Water Conservation Victoria Goulburn-Murray Water South Australia Planning SA 6) Tasmanian irrigation area boundaries. These are contained in three separate data sets: Irrigation Boundary, Cressy - Longford; Irrigation Boundary, Coal River Valley; and Irrigation Boundary, Winnaleah. The data sets were supplied by the Tasmanian Department of Primary Industries, Water and Environment, in ARC/INFO export format. Positional Accuracy The positional accuracy is given as an attribute of the line features and ranges from 12.5 m to 5000 m for 90% or more of identifiable points. The specified positional accuracy varies with source data as follows. 1) Ord River Scheme, Stage 1, irrigation area boundaries. The positional accuracy is unknown but was estimated to be about 35 m based on the spacing of vertices. 2) Boundary of Gazetted Irrigation Areas in Queensland. The stated positional accuracy varies with the scale of source material and is, at worst, 251 m at a 95% confidence level. The positional accuracy of the boundaries was shown as 450 m in the national data set because the coordinate datum is not known with certainty. 3) Northern Murray-Darling Basin irrigation area boundaries. The stated positional accuracy is 5000 m or thereabouts for 90% of identifiable points. 4) Northern New South Wales Cotton Development data set. The stated positional accuracy of this data set is 25 m. 5) Southern Murray-Darling Basin irrigation area boundaries. The stated positional accuracy varies according to the origin of the data. For boundaries in South Australia, it is 12.5 m for 90% of identifiable points; for Victoria, 25 m for 90% of identifiable points; and for New South Wales, 50 m for 90% of identifiable points. 6) Tasmanian irrigation area boundaries. The stated positional accuracy was 12.5 m for 90% of the identifiable points. Attribute Accuracy Attribute accuracy has not been thoroughly tested. The construction of the data set from the source data, however, was automated using macros, so that errors were minimised. An automated test of the conversion of attributes from the supplied format to the final data set format for polygons in both the Boundary of Gazetted Irrigation Areas in Queensland data set and the Northern New South Wales Cotton Development data set showed no errors. Spot checks of the attribute values in the final product as compared with the source data did not reveal any errors. The attribute accuracy of some of the component data sets is known, see following list. 1) Ord River Scheme, Stage 1, irrigation area boundaries. This data set has no user-defined attributes. Information about the type of irrigation practised was obtained from the book "Ord River Irrigation Project" published by the Governments of Western Australia and the Northern Territory in 1996. 2) Boundary of Gazetted Irrigation Areas in Queensland. Attribute accuracy stated to be 100% for name of irrigation area. The metadata provided with the data set states that the boundaries represent designated ("gazetted") irrigation areas as opposed to actual irrigation areas. 3) Northern Murray-Darling Basin irrigation area boundaries. This data set has no user-defined attributes but was stated to show actual irrigation areas as opposed to designated irrigation areas. 4) Northern New South Wales Cotton Development data set. This data set has only one user-defined attribute; the values include type of irrigation and whether or not the irrigated crop is cotton. The data set was stated to show actual irrigation areas as opposed to designated irrigation areas. The attribute accuracy was stated to be unknown. 5) Southern Murray-Darling Basin irrigation area boundaries. Attribute accuracy not stated. This data set has only one user-defined attribute, the name of the irrigation area. There are no other attributes but the data set was stated to show designated irrigation areas as opposed to actual irrigation areas. It was assumed that all named polygons represent designated irrigation areas. The data set has approximately 70 polygons with a null value of the name attribute. For each of these, assumptions were made as to whether or not the polygon represented an irrigation area. The assumptions were as follows. If the polygon shared at least part of its boundary with the universe polygon, it was assumed to be an irrigation area. If the polygon was an island within another such polygon with null value of the name attribute, it was again assumed to be an irrigation area. If the polygon shared its outer borders only with polygons for which the name attribute was not null, it was assumed to be a void. 6) Tasmanian irrigation area boundaries. These data sets have no user-defined attributes. They were stated to show designated irrigation areas as opposed to actual irrigation areas and the type of irrigation for each of the three areas was also stated. The names of the irrigation areas were given in the metadata provided with the data sets. Attributes of the polygon features in the vector version of the data set are: status - status of irrigation area irrigation_type - type of irrigation name - irrigation area name Logical Consistency Tests have shown that: * All lines intersect at nodes * No lines are duplicated * No lines overshoot or undershoot * All lines are labelled * All polygon boundaries close * All polygons are labelled * No polygons have duplicate labels * All lines and polygons are topologically related Whether there are any instances of lines crossing unintentionally has not been tested. Completeness Coverage is incomplete in two ways. First, irrigation is practised to a significant extent outside the areas shown in this data set. Second, irrigation is not practised throughout the full extent of the areas shown. These remarks apply especially to the coverage of Tasmania and the southern Murray-Darling Basin where the irrigation areas shown are designated irrigation areas. They also apply to the coverage of those parts of the northern Murray-Darling Basin where the irrigation areas shown are actual irrigation areas derived from coarse scale source material (stated positional accuracy 5000 m). Classification is complete. Any errors, omissions or suggestions for improvement should be made known directly to BRS (by email to dataman@brs.gov.au or by mail to the Data Manager, Bureau of Rural Sciences). Contact Information Contact Organisation Bureau of Rural Sciences Contact Position Data Manager Mail Address 1 PO Box E11 Mail Address 2 - Suburb or Place or Locality KINGSTON State or Locality 2 ACT Country Australia Postcode 2604 Telephone 612 6272 4232 Facsimile 612 6272 4687 Electronic Mail Address info.abares@agriculture.gov.au Metadata Date 29NOV2001 Additional Metadata Australian Irrigation Areas, Version 1a, User Guide.