Hong Kong Districts - Latitude / Longitude

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  1. #11

    Join Date
    Nov 2003
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    Not friggin' Lamma no more!
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    You're welcome!


  2. #12

    Join Date
    Sep 2004
    Location
    Hong Kong
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    58

    Maybe you should email to the survey and mapping office of Lands department to see whether they sell the lat/Long data. I am very sure that they should have it. However they don't sell it as one of the standard product.

    Another option is to use some pocketPC HK map software. I know HK hiking guide do list the Lat/long of selected location. I am not sure about MapKing though.

    Yeah, Google Earth can help, but it would probably makes your eyes really tired. hee hee.


  3. #13

    Join Date
    Jun 2005
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    Quote Originally Posted by KnowItAll:
    In english please?
    Maybe I'm just an out and out geek (and a hiker who's interested in maps) but I find this document: http://www.geodetic.gov.hk/smo/gsi/d...atorynotes.pdf linked on from one of your links, to be a fascinating read.

    If the Earth were a perfect sphere accurate mapping and longtitude/latitude calculations would be straightforward, but unfortunately, the Earth is actually an ellipsoid, and over time as our instrumentation and measurement techniques improve the "reference ellipsoid" that is used to calculate latitude and longitute is refined. Hong Kong Grid 1980 and WGS84 refer to two different mathematical definitions of the shape of the Earth, which in turn lead to different definitions of the latitude and longitude of every place on its surface (except that there is a fixed point defined as zero longitude which is at Greenwich Observatory in London I believe, and the geographic poles are fixed at 90 degrees latitude).

    Moreover, in most general mapping applications for use on land (at least, before the advent of GPS) people did not use latitude and longitude (unlike marine navigation, which always has, at least since people realised the Earth was basically round). The system used for indentifying locations on most maps is the UTM Grid ( http://en.wikipedia.org/wiki/Univers...rdinate_system ).

    If you go hiking in the Country Parks you will see that all the distance posts now have a UTM-based Grid Reference on them which identifies their location, which can be used to assist navigation, rescue services, etc. For example, distance post 001 on the Lantau Trail is at HE 091 651. That identifies a 100m*100m square on the map (In fact to be unambiguous you need a 49Q on the front of that to identify the UTM Zone: http://www.colorado.edu/geography/gc...f/utmzones.gif ). In principle you could add more digits to give further precision: HE 0914 6517 identifies a 10m*10m area. You need to have a system like this when navigating on land using a map because you are projecting a spheroid onto a flat piece of paper.

    Er, I'm not sure that answered the question though...

  4. #14

    any new suggestions ?

    need a geo fence of the 18 Hong Kong districts

    or the official boundary's of the districts