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braindump [2017/02/08 06:02]
allchin09 [Prominence]
braindump [2018/10/10 10:33] (current)
allchin09 [Australian National Grid (ANG)]
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 However, the mapping section has already be moved from Prince Albert Rd Sydney, out to Bathurst. No longer can one walk into an LPI building in Sydney to make mapping related enquiries, or to look at aerial images through a set of stereo glasses. However, the mapping section has already be moved from Prince Albert Rd Sydney, out to Bathurst. No longer can one walk into an LPI building in Sydney to make mapping related enquiries, or to look at aerial images through a set of stereo glasses.
 +
 +==== Half of NSW topographic maps no longer printed ====
 +From 3rd September 2018, 524 out of their 1,094 titles for the state were only made available in digital form from Spatial Services. By area, this covered about 3/4 of the state.
 +
 +A notice regarding the change can be found [[http://​spatialservices.finance.nsw.gov.au/​__data/​assets/​pdf_file/​0008/​219455/​SpatialServices_Topoletter.pdf|here]]
 +
 +[[http://​maps.ozultimate.com/?​id=1534338535930|Interactive map of '​digital only' maps]]
 +
 +{{ ::​digitalonlymaps.jpg |}}
 ===== Geographic Names Board ===== ===== Geographic Names Board =====
  
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     * Work is going to be done (timeframe not specified) on "​bringing the GNR (Geographic Names Regester) into the 21st century     * Work is going to be done (timeframe not specified) on "​bringing the GNR (Geographic Names Regester) into the 21st century
     * Many errors in the listed coordinates are due to the location being recorded in lat/long to the nearest minute but in the top left corner of the grid square, as opposed to the bottom left as convention dictates.     * Many errors in the listed coordinates are due to the location being recorded in lat/long to the nearest minute but in the top left corner of the grid square, as opposed to the bottom left as convention dictates.
 +
 +  * AA spoke with staff member from GNB on the matter (Apr 2018):
 +    * Acknowledged the issue and the plans for a project to address it
 +    * No funding available in the current political climate
  
 ====== Licensing ====== ====== Licensing ======
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     * Elevation Data     * Elevation Data
       * [[http://​www.ga.gov.au/​elvis/​|ELVIS - Elevation Information System]]       * [[http://​www.ga.gov.au/​elvis/​|ELVIS - Elevation Information System]]
 +
 +====== Terminology ======
 +Well defined and consistant terminology goes a long way to assist in clear and well understood communication.
 +
 +Refer to the [[terminology]] page for further information.
  
 ====== Datums ====== ====== Datums ======
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 ==== AGD66 ==== ==== AGD66 ====
  
-The datum used on topographic maps before GDA94. 2nd Edition topographic maps use the AMG66 projection which is derived from AGD66.+The datum used on topographic maps before GDA94. ​1st and 2nd Edition topographic maps use the AMG66 projection which is derived from AGD66.
  
 ==== Australian National Grid (ANG) ==== ==== Australian National Grid (ANG) ====
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 [[http://​www.binaryearth.net/​AusDatumTool/​AustralianNationalGrid.html]] [[http://​www.binaryearth.net/​AusDatumTool/​AustralianNationalGrid.html]]
  
-The ANG makes use of the Clarke 1858 spheroid.+The ANG makes use of the Clarke 1858 spheroid, where the parameters are expressed in British feet for mainland Australia (and Clarkes feet for Tasmania).
 ===== Datum Conversions ===== ===== Datum Conversions =====
  
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 ===== Web Mercator (EPSG:​3857/​EPSG:​900913) ===== ===== Web Mercator (EPSG:​3857/​EPSG:​900913) =====
  
-Used in many popular web mapping applications (Google/​Bing/​OpenStreetMap). Uses spherical development of ellipsoidal coordinates. Relative to an ellipsoidal development errors of up to 800 meters in position and 0.7 percent in scale may arise. It is not a recognized geodetic system: see WGS 84 / World Mercator (CRS code 3395).+Used in many popular web mapping applications (Google/​Bing/​OpenStreetMap). Uses spherical development of ellipsoidal coordinates. Relative to an ellipsoidal development errors of up to 40 km may arise. It is not a recognized geodetic system: see WGS 84 / World Mercator (CRS code 3395). 
 + 
 +For details on the issues using Web Mercator for geospatial applications,​ see the report from the US NGA (National Geospatial-Intelligence Agency) on [[http://​earth-info.nga.mil/​GandG/​wgs84/​web_mercator/​(U)%20NGA_SIG_0011_1.0.0_WEBMERC.pdf|Implementation Practice 
 +Web Mercator Map Projection]]
  
 ===== Universal Transverse Mecator (UTM) ===== ===== Universal Transverse Mecator (UTM) =====
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 ^Parameter ​             ^ Clarke 1858   ^ ANS      ^ GRS80       ^ WGS84       ​| ​ ^Parameter ​             ^ Clarke 1858   ^ ANS      ^ GRS80       ^ WGS84       ​| ​
-^Major Semi Axis        | 6378293.645 ​  | 6378160 ​ | 6378137 ​    | 6378137 ​    |+^Major Semi Axis (m)    ​| 6378293.645 ​  | 6378160 ​ | 6378137 ​    | 6378137 ​    |
 ^Inverse Flattening ​    | 294.26 ​       | 298.25 ​  | 298.2572221 | 298.2572236 | ^Inverse Flattening ​    | 294.26 ​       | 298.25 ​  | 298.2572221 | 298.2572236 |
 ^Used in                | ANG           | AGD, AMG | GDA, MGA    | GPS         | ^Used in                | ANG           | AGD, AMG | GDA, MGA    | GPS         |
braindump.1486533734.txt.gz · Last modified: 2017/02/08 06:02 by allchin09