=====================
Technical Description
=====================

Property is created through processing property data sourced from Australia’s States and Territories. Source attributes are mapped and standardised to provide a coherent definition across the jurisdictional supplies, with associated geometry being cleaned and processed to output a topologically consistent layer of Australia’s property boundaries at a national scale.

Each property record has a boundary representing the overall coverage of the single property and a Contributor ID which is the jurisdiction’s reference to the property for land valuation and other property purposes. The Contributor ID can be utilised for searches in the relevant jurisdiction’s land valuation system to provide the indicative value of the property for rating purposes.

Property is updated and released regularly and has integrated relationships with other Geoscape Products. Further information regarding attributes, quality, coverage and product release details are outlined below.


--------
Linkages
--------

Property is integrated with the following Geoscape products:

- Cadastre
- G-NAF
- Buildings


The joins used to link to these products are shown below, with attributes used in the joins described.

.. image:: technical_description/property_linkages.png
    :align: center

The property_pid attribute can be used to link to a cadastre_pid in the Cadastre product where a relationship between Property and Cadastre exists. These relationships are represented within the property_cadastre table within the Property product. The three possible relationships between Cadastre and Property are:

- one cadastral parcel is equal to one property
- many cadastral parcels make up one property
- one cadastral parcel contains many properties


----------
Attributes
----------


Contributor ID
--------------

The Contributor ID is the property identifier provided by the jurisdiction that is searchable for land valuation and rates purposes. The associated attribute(s) in the jurisdiction source data for each State or Territory are found in the table below.

.. list-table::
    :header-rows: 1

    *   - State
        - Jurisdiction Value
    *   - ACT
        - TITLE_NUMBER [#]_
    *   - \ \
        - BLOCK + “/” + SECTION + “/” + DIVISION_CODE [#]_
    *   - NSW
        - PROPID
    *   - NT
        - VOLUME_TYP + “/” + VOLUME_NO + “/” + FOLIO_NO
    *   - QLD
        - PROPERTY_ID
    *   - SA
        - ASSNO_TENSEQNO
    *   - TAS
        - PID
    *   - VIC
        - PFI
    *   - WA
        - VPU_VE_NUMBER


.. [#] Derived from the following dataset: 'ACT_PROPERTY'


.. [#] Derived from the following dataset: 'BLOCKS'


Source
------

The name of the State or Territory that the property data was sourced from.
Base Property
The Base Property allows for a simple visualisation of property coverage across all States and Territories without overlapping parcels. Only property parcels which are not contained by another property can be part of the base representation.


Area
----

The area of each property polygon in square meters, calculated from the feature geometry using an equal area projection. The total area in square meters can be calculated by summing property parcels with a common Property PID.


----------
Data Model
----------

.. graphviz::

    digraph G {
    fontname="ROBOTO" fontsize="10pt"
    node [fontname="ROBOTO" fontsize="8pt"]
    edge [fontname="ROBOTO" fontsize="8pt"]
    rankdir=LR

    graph [pad="0.5", ranksep="1"];

    subgraph cluster_property { label="Property"
        graph[style="dashed,rounded"  color="#EA6B66"]

    property [shape=plain
    label=<<TABLE BGCOLOR="#7EA6E0"
    BORDER="1"
    CELLBORDER="0"
    style="rounded"
    CELLSPACING="0"
    CELLPADDING="5">

    <TR>
    <TD  COLSPAN="2">property</TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" >PK</TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >property_polygon_pid: varchar (15)  </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" >FK</TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >property_pid: varchar (15) </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" ></TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >contributor_id: varchar (50) </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" ></TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >date_created: date </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" ></TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >date_modified: date </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" ></TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >state: varchar (3) </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" ></TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >source: varchar (20) </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" ></TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >base_property: varchar (3) </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" ></TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >area: number (14,2) </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" ></TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >geometry: Polygon </TD>
    </TR>

    </TABLE>>];

    property_cadastre [shape=plain
    label=<<TABLE BGCOLOR="#FFD966"
    BORDER="1"
    CELLBORDER="0"
    style="rounded"
    CELLSPACING="0"
    CELLPADDING="5">

    <TR>
    <TD  COLSPAN="2">property_cadastre</TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" >PK</TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >property_cadastre_pid: varchar (15)    </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" ></TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >date_created: date </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" >FK</TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >property_pid: varchar (15) </TD>
    </TR>

    <TR>
    <TD BGCOLOR="white" >FK</TD>
    <TD BGCOLOR="white" ALIGN="LEFT" >cadastre_pid: varchar (15) </TD>
    </TR>

    </TABLE>>];

    }

    property -> property_cadastre [arrowhead=crownoneodot dir=both arrowtail=crownoneodot]

    subgraph cluster_legend {
        graph[style="" label="Legend" ]

    legend [shape=plain
            label=<<TABLE
                CELLBORDER="0"
                Border="0">
            <TR>
                <TD BGCOLOR="#7EA6E0" BORDER="1">     </TD>
                <TD>Spatial Attribute Table</TD>
            </TR>

            <TR>
                <TD BGCOLOR="#FFD966" BORDER="1">     </TD>
                <TD>Textual Attribute Table</TD>
            </TR>

            </TABLE>>]


           key [shape=plain  label=<<table border="0" cellpadding="1" cellspacing="0" cellborder="0">
          <tr><td port="i1"> Zero or Many </td> </tr>

          </table>>]

        key2 [shape=plain label=<<TABLE border="0" cellpadding="1" cellspacing="0" CELLBORDER="0">
          <tr><td port="i1"> </td></tr>

          </TABLE>>]

        key:i1 -> key2:i1 [arrowhead=crownoneodot]


      }


    }


---------------
Data Dictionary
---------------

.. csv-table:: property
    :header-rows: 1
    :widths: 150,100,300,100,100,100
    :file: technical_description/table_property.csv

.. csv-table:: property_cadastre
    :header-rows: 1
    :widths: 150,100,300,100,100,100
    :file: technical_description/table_property_cadastre.csv

-------------
Domain Values
-------------


state
-----

.. csv-table::
    :header-rows: 1
    :file: technical_description/domain_state.csv


source
------

.. csv-table::
    :header-rows: 1
    :file: technical_description/domain_source.csv


base_property
-------------

.. csv-table::
    :header-rows: 1
    :file: technical_description/domain_base_property.csv


----------------
Update Frequency
----------------

Property is continuously updated and released with the most up to date data available on a monthly schedule.

-------------
Data Quality
-------------

Positional Accuracy
------------------

Property has been created by combining land valuation/rates information with Cadastre. To achieve a single property representation a union of multiple Cadastre boundaries happens during production. This will preserve the outer boundaries accuracies as supplied by the jurisdiction. Geoscape makes minor changes only where they are required to create valid features described in Property Geometry Validity.

Coordinates Referencing the GDA2020 Datum
---------

Spatial features referencing the GDA2020 datum are produced using a coordinate transformation from the GDA94 datum using the following parameters.

    | shift_x = 0.06155,
    | shift_y = -0.01087,
    | shift_z = -0.04019,
    | rotate_x = -0.0394924,
    | rotate_y = -0.0327221,
    | rotate_z = -0.0328979,
    | scale_adjust = -0.009994

Property Geometry Validity
--------------------------

Property geometry is validated to ensure polygons are a valid representation and free of self-intersection. Issues being detected and resolved include spikes, bow ties, duplicate vertices, null geometries, multipart geometries, and self-contacts. Minor overlaps are also resolved where a property has a Base Property of ‘Yes’. Overlapping polygons will persist in the product as they can be valid geometries representing the jurisdictions intent.

Polygon orientation conforms to the following specifications:

- `OGC Simple Feature Access Specification v1.2.1 <https://portal.ogc.org/files/?artifact_id=25355>`_ [Section - 6.1.11.1]
- `The GeoJSON Specification RFC7946 <https://datatracker.ietf.org/doc/html/rfc7946>`_ [`Section 3.1.6 <https://datatracker.ietf.org/doc/html/rfc7946#section-3.1.6>`_ dot point 4]

This means the polygon outer boundary will be counter clockwise and the inner boundary will be clockwise for file formats that support the above standards.

Further Comments
----------------

Property has been processed to assure all polygons are stored as single part features to improve capability with a range of software applications. Due to this there is duplication of the Property PID and Contributor ID information.

-----------------------------
Extent/Geographic Description
-----------------------------

The spatial coverage of Property includes Australia’s land mass and surrounding offshore islands.

The Bounding Box for this data is as follows:

- North bounding latitude: -8˚
- South bounding latitude: -45˚
- East bounding longitude: 155˚
- West bounding longitude: 112˚

.. image:: technical_description/extent_map.png
    :align: center

A detailed description of the coverage for each State and Territory is provided in the table below.

.. csv-table::
    :header-rows: 1
    :width:
    :file: technical_description/property_extent.csv

------------------------
Spatial Reference System
------------------------

GDA94
----

Horizontal Datum: The Geocentric Datum of Australia 1994 (GDA94) is the target horizontal datum.

Coordinate System: Geographic Coordinate System Geocentric Datum of Australia 1994 (GDA94).

GDA2020
-----

Horizontal Datum: The Geocentric Datum of Australia 2020 (GDA2020) is the target horizontal datum.

Coordinate System: Geographic Coordinate System Geocentric Datum of Australia 2020 (GDA2020).

----------------
Delivery Format
----------------

Property is provided at a National and State/Territory level, depending on the file format selected. The data is made available in the File Geodatabase, GeoJSON, ESRI Shapefile and MapInfo TAB formats described below.

.. csv-table::
    :header-rows: 1
    :file: technical_description/property_formats.csv



File Geodatabase
----------------

| **Format name**
| File Geodatabase – ESRI™
|
| **Specification**
| This format includes files with the following extensions: \*.gdb
| ESRI File Geodatabase Technical Description. Follow this link: http://desktop.arcgis.com/en/desktop/latest/manage-data/administer-file-gdbs/file-geodatabases.htm
|
| **Language**
| English


GeoJSON
-------

| **Format name**
| GeoJSON
| **Specification**
|
| This format includes files with the following extensions: \*.geojson
| GeoJSON specification: https://tools.ietf.org/html/rfc7946
|
| **Language**
| English

.. note:: The GeoJSON specification states that the coordinate reference system for all GeoJSON coordinates is:
    “a geographic coordinate reference system, using the World Geodetic System 1984 (WGS 84) datum, with longitude and latitude units of decimal degrees”
    Cadastre will be provided with coordinates using the datum selected for download (GDA94/GDA2020) with longitude and latitude units of decimal degrees.


JSON
-----

| **Format name**
| JSON
|
| **Specification**
| This format includes files with the following extensions: \*.json
| JSON specification: https://www.json.org/json-en.html
|
| **Language**
| English

ESRI Shapefile
--------------

| **Format name**
| Shape – ESRI™
|
| **Specification**
| This format includes files with the following extensions: \*.shp, \*.shx, \*.dbf
| ESRI Shapefile Technical Description, an ESRI White Paper, July 1998. Follow this link: https://www.esri.com/library/whitepapers/pdfs/shapefile.pdf
|
| **Language**
| English

MapInfo TAB
-----------

| **Format name**
| TAB – MapInfo Professional™
|
| **Specification**
| This format includes files with the following extensions: \*.tab, \*.dat, \*.id, \*.map
| The MapInfo TAB format is a popular geospatial vector data format for geographic information systems software. It is developed and regulated by MapInfo as a proprietary format. TAB files support geospatial standards such as Open GIS, the OGC, ISO, W3C and others.
|
| **Language**
| English

Geopackage
----------------

| **Format name**
| Geopackage
|
| **Specification**
| This format includes files with the following extensions: \*.gpkg
| OGC Geopackage Standards. Follow this link: https://www.geopackage.org/
|
| **Language**
| English

------------------
Product Versioning
------------------

Property versioning is managed through incrementing when there is a change to the product schema or a significant change in data population, these are described further below:

- A schema change can affect a major or minor increment to the versioning. Additive changes (changes that won’t break customers’ ability to work with the data) will be incremented with a minor version increment, an example is the addition of a new attribute. Removal of attributes or changing the structure of the Property schema will enact a major change to identify that this requires the attention of all customers and partners.
- Where a significant geography of Australia either has a new population of data for an attribute or is populated from a much higher quality source a minor increment will be applied to the product version.

Therefore, Property versioning will not increment with every data update, published releases will have a name e.g. ‘May 2021’ and will reference a version of the Property product e.g. ‘1.0’.