braindump
Differences
This shows you the differences between two versions of the page.
Both sides previous revisionPrevious revisionNext revision | Previous revisionLast revisionBoth sides next revision | ||
braindump [2017/02/08 09:43] – [Geographic Names Board] allchin09 | braindump [2021/03/07 22:02] – [Topographic maps] 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. | 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:// | ||
+ | |||
+ | [[http:// | ||
+ | |||
+ | {{ :: | ||
===== Geographic Names Board ===== | ===== Geographic Names Board ===== | ||
Line 40: | Line 49: | ||
* Work is going to be done (timeframe not specified) on " | * Work is going to be done (timeframe not specified) on " | ||
* 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 ====== | ||
Line 51: | Line 64: | ||
===== Topographic maps ===== | ===== Topographic maps ===== | ||
- | * 1:63360 (2 inch:mile) | + | * 1:63360 (1 inch:mile) |
* 1st edition | * 1st edition | ||
* 2nd edition (not all were revised | * 2nd edition (not all were revised | ||
* Note that the maps don't cover the whole of the state, they are mostly focused towards the coast. Also, there are a few ' | * Note that the maps don't cover the whole of the state, they are mostly focused towards the coast. Also, there are a few ' | ||
- | * 1:31680 (1 inch:mile) | + | * 1:31680 (2 inch:mile) |
* 1:50000 Army/RASC | * 1:50000 Army/RASC | ||
* 1st edition (ANG) | * 1st edition (ANG) | ||
Line 87: | Line 100: | ||
* Elevation Data | * Elevation Data | ||
* [[http:// | * [[http:// | ||
+ | |||
+ | ====== 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 ====== | ||
Line 124: | Line 142: | ||
==== 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. |
==== Australian National Grid (ANG) ==== | ==== Australian National Grid (ANG) ==== | ||
Line 134: | Line 152: | ||
[[http:// | [[http:// | ||
- | 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 ===== | ||
Line 162: | Line 180: | ||
===== Web Mercator (EPSG: | ===== Web Mercator (EPSG: | ||
- | Used in many popular web mapping applications (Google/ | + | Used in many popular web mapping applications (Google/ |
+ | |||
+ | For details on the issues using Web Mercator for geospatial applications, | ||
+ | Web Mercator Map Projection]] | ||
===== Universal Transverse Mecator (UTM) ===== | ===== Universal Transverse Mecator (UTM) ===== | ||
Line 179: | Line 200: | ||
^Parameter | ^Parameter | ||
- | ^Major Semi Axis | 6378293.645 | + | ^Major Semi Axis (m) |
^Inverse Flattening | ^Inverse Flattening | ||
^Used in | ANG | AGD, AMG | GDA, MGA | GPS | | ^Used in | ANG | AGD, AMG | GDA, MGA | GPS | | ||
Further information on geodesy can be found here - [[https:// | Further information on geodesy can be found here - [[https:// | ||
+ | |||
+ | ====== Prominence ====== | ||
+ | |||
+ | ===== What is it? ===== | ||
+ | |||
+ | In the geographical context, //the prominence of a mountain is the elevation differential between the mountain’s summit elevation and its highest pass/saddle connecting it to its parent.// | ||
+ | |||
+ | [[http:// | ||
+ | |||
+ | It is of use to bushwalkers as it provides an indication of relative difficulty in the effort required to reach a peak. By applying among other things a prominence criteria, a list of peaks that meet that criteria can be complied. An example is The Abels of Tasmania, where only peaks over 1100m altitude but with a prominence greater than 150m are included. | ||
+ | |||
+ | The prominence criteria is important as it removes high peaks that are near to each other in altitude and would require little elevation gain to travel between them. | ||
+ | |||
+ | ===== How is it calculated? ===== | ||
+ | |||
+ | [[https:// | ||
+ | |||
+ | [[https:// | ||
+ |
braindump.txt · Last modified: 2021/03/07 22:06 by allchin09