Differences

This shows you the differences between two versions of the page.

--- braindump [2018/10/08 23:23] – [Web Mercator (EPSG:3857/EPSG:900913)] allchin09
+++ braindump [2018/10/09 16:16] – [Datums] allchin09
@@ Line 27: / Line 27: @@
 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 =====
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     * Elevation Data
       * [[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 ======
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 ===== 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