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| Perlis-Kedah border |
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| Zoomed in |
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| Perlis User Defined Coordinate System |
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| Kedah User Defined Coordinate System |
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| Kelantan-Terengganu border |
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| Zoomed in |
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| Malacca-Johore border |
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| Zoomed in |
Is there a state boundary issue?
I have often been told by many that the boundary between state cadaster maps do not dovetail because each state uses different reference points for their respective cadaster. It seemed logical so I never care to question it furthermore, was mentioned by people more experienced than me. However, today, since I as usual got nothing better to do, gave it a try and activated 6 state cadaster maps (with their User Defined Coordinate System NOT WGS 84 projection) as shown above where QGIS showed each had different user defined coordinate system but unlike what people said, all fit well along their borders. So I asked myself 'Where did I go wrong?' Firstly, I did not try it out myself to see that the proof was in the pudding. Secondly, I did not question people I thought were 'experts' and more experienced than me. Thirdly, I never thought that JUPEM in coming up with respective projection for state cadaster plans, had aligned them properly. Now I believe the moment the original JUPEM plan is converted away from the user defined coordinate system, say, "WGS84", be prepared for errors where cadaster or landuse plans do not converge and dovetail with their adjacent neighbour. For reference, I also happened to get JUPEMs projection parameters from one of my staff who obtained them directly from the horse's mouth as below:
"--- Malaysia RSO Projection ---"
"Peninsular Malaysia", 7, 47, 7, 105.236442875, -0.0001719694, 323.130102389, 0.99984, 804671.29978, 0
"Sabah & Sarawak", 7, 96, 7, 115.0, 4.0, 53.3158204722, 0.99984, 2590476.872, 5442857.653, 0
"--- Malaysia State Cassini-Soldner Systems ---"
"Cassini-Soldner Johor", 30, 47, 7, 103.5627583,2.0425,0,0
"Cassini-Soldner NS/Melaka", 30, 47, 7, 101.9411667,2.712283333,-242.0048934,-948.546528
"Cassini-Soldner Pahang", 30, 47, 7, 102.4361778,3.710972222,0,0
"Cassini-Soldner Selangor", 30, 47, 7, 101.5082444,3.680344444,-21759.43848,55960.90576
"Cassini-Soldner Kelantan", 30, 47, 7, 102.1772917,5.893922222,0,0
"Cassini-Soldner Terengganu", 30, 47, 7, 102.8952083,4.946141667,0,0
"Cassini-Soldner Perak (Revised)", 30, 47, 7, 100.8167667,4.859380556,0,133453.6688
"Cassini-Soldner Penang", 30, 47, 7, 100.3458694,5.421325,0,0
"Cassini-Soldner Kedah/Perlis", 30, 47, 7, 100.6375944,5.965147222,0,0
"Cassini-Soldner Singapore", 30, 47, 7, 103.853, 1.287639, 30000, 30000
terbaik
ReplyDeleteI still don't have an original raster map to work on i.e. can only activate with "Add Raster Layer" icon.
DeleteFirstly I must say thank you for your blog and it is the most educational I have followed to learn about GIS and QGIS. Thanks so much for the time and effort you take to help share your knowledge.
ReplyDeleteMy question is, are these Malaysia State Cassini-Soldner projections still current , or have they changed since 2013? I assume these are GDM2000? I am trying to find the most up to date Cassini Johor projection and Kertau1948 datum, rather than the GDM2000 dataum. Seems very hard to find.
For the record, I pensioned in 2015 so don't know the current situation. But your question is too general: Adoption of the GDM2000 is by individual state Survey Dept so one state Survey Dept. may be adopt it while another has not adopted it...yet. The Federal Survey Dept merely keeps a copy of the latest survey map from the state Survey Dept so your best bet is to contact the Johore State Survey Dept. Best f luck.
ReplyDelete