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Cassini Projection in ArcInfo 9.2   zaki ghazali Mar 17, 2008
Re: Cassini Projection in ArcInfo 9.2   Melita Kennedy Mar 18, 2008
Re: Cassini Projection in ArcInfo 9.2   Cheng Siang Leow Apr 27, 2010
Re: Cassini Projection in ArcInfo 9.2   Melita Kennedy Apr 27, 2010
Re: Cassini Projection in ArcInfo 9.2   Cheng Siang Leow Apr 27, 2010
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Subject Cassini Projection in ArcInfo 9.2 
Author zaki ghazali 
Date Mar 17, 2008 
Message Dear Mellita & All

I would like to find out the Cassini formulae adopted by ArcInfo Desktop version 9.2. The set of Cassini (Cassini-Soldner actually) formulae that we use here in Malaysia has been derived by Richadus and Adler (1974) and I am curious to know if the same formulae is adopted by ArcInfo Desktop version 9.2.

Thanks.

Zaki Ghazali 
   
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Subject Re: Cassini Projection in ArcInfo 9.2 
Author Melita Kennedy 
Date Mar 18, 2008 
Message Hello!

It's described in John Snyder's Map Projections: A Working Manual, USGS PP 1935. It's now on-line at

http://pubs.er.usgs.gov/djvu/PP/PP_1395.pdf

Look starting at PDF page 101 (book page 92).

Melita 
  Melita Kennedy
ESRI Product Specialist 
   
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Subject Re: Cassini Projection in ArcInfo 9.2 
Author Cheng Siang Leow 
Date Apr 27, 2010 
Message Hie, since i can't create new thread, i'm forced to 'hijack' your thread sir, real sorry. I hope someone do read this. i'm from Malaysia by the way. My question is on the inter-projection of -WGS84-rso- and state cassini.

My problem. I have SRTM DEM (WGS84), a SPOT 5 image (RSO, labelled as Kertau_RSO_Malaya_Meter) and a cadastral sheet in Kedah state cassini (labelled as GDM_2000_State_cassini_Perlis in projection by ArcGIS)

Once i defined my layers coor system, i had no problem displaying 3 maps on each other. While i can convert WGS84 to RSO and vice versa without problem, i can't manage to convert WGS84 and RSO into cassini.

ArcGIS seems to be able to tell exactly what type of projection i intended to make, but when i click "OK" i was told "Undefined Geographic Transformation", although the geographic transformation drop down list was labelled '(optional)'. i couldn't find anything that resembles "WGS to GDM"

The fact that ArcMap manages to put the 3 maps together suggests that these the program recognises the 3 projections, but how is it to project between these, i couldn't figure out. has been a while since i tried, trying to convert everything into WGS and re-project into cassini, but still it wont work. Need help here.

Hope to get some reply from the experts.

p/s: i'm kind of an end user with minimal knowledge of GIS, i'm just interested in application of GIS. So if you could just provide some simple guide for me to project all 3 maps into cassini, it'll be great. Too much of 'projection theory' will be overkill for me. thanks, again. 
   
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Subject Re: Cassini Projection in ArcInfo 9.2 
Author Melita Kennedy 
Date Apr 27, 2010 
Message Hello,

Malaysia government does not publicly release any datum transformations. There are a few not-very-accurate transformations available from other groups for Kertau, but nothing for GDM2000. The Project Tool is designed to force you to provide a transformation if the input and output geographic coordinate systems (datums) are different.

If you have information on a transformation, you can use the Create Custom Geographic Transformation Tool to define a new transformation.

If your data is lining up well enough that you can ignore any differences, try exporting the reprojected data in ArcMap, rather than use the Project Tool. Here's how to do it. Right click the layer in ArcMap table of contents. Select Data, Export Data. In the dialog, select "use the data frame's coordinate system" radio button. Fill out the rest of the dialog.

Melita 
  Melita Kennedy
ESRI Product Specialist 
   
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Subject Re: Cassini Projection in ArcInfo 9.2 
Author Cheng Siang Leow 
Date Apr 27, 2010 
Message thank you VERY MUCH!. i didn't know there's such alternative road. thanks alot! Will try it out later.