Clarke 1866 UTM z50 projection parameters

[Kiter Slack]

Hi,

I am trying to figure out the line to add to the MapInflow.prj file

my guess is but I am unsure about these things:

"--- Universal Transverse Mercator (CLARKE 1866) ---"
 "UTM Zone 50N, (CLARKE 1866)", 8,999, 7,0,0,0,7, 117, 0, 0.9996, 500000, 0

Can anyone assist? Cheers

[Kiter Slack]

Also need zone 32S for Clarke 1880 and my guess is

"--- Universal Transverse Mercator (CLARKE 1880) ---"
 "UTM Zone 32S, (CLARKE 1880)", 8,999, 6,0,0,0,7, 9, 0, 0.9996, 500000, 10000000

So if anyone could make comment on this too it would be so greatly appreciated.

[Kiter Slack]

Ok I have been doing some more research and now I am using

"--- Universal Transverse Mercator (CLARKE 1880) ---"
 "UTM Zone 32S My guess, (CLARKE 1880)", 8,6,7, 9, 0, 0.9996, 500000, 10000000

and

"--- Universal Transverse Mercator My Guess (CLARKE 1866) ---"
 "UTM Zone 50N, (CLARKE 1866)", 8,7,7, 117, 0, 0.9996, 500000, 0

since I don't nee to use the 999 custom projections and I think the result is the same since I made no shift.  Would be gret if someone can confirm all this.  Cheers Slack

On Sunday, 13 July 2014 13:39:20 UTC+8, Kiter Slack wrote:

[David Sherrod]

Slack,

It almost impossible to confirm your choices since the Listserv has no idea about your map, the source of the coordinate info, or where you hope to finish. Or did some part of this recent thread go AWOL?

 

 UTM 32S (South) is coastal west Africa.  For projection line, it seems odd you have chosen Datum No. 6 (Arc 1960), which was (is) generally used for mapping in Kenya and Tanzania (East Africa)

You might read Cliff Mugnier’s article for some datum ideas specific to UTM 32S,

http://www.asprs.org/a/resources/grids/03-2001-angola.pdf

 

More appropriate datums might be No. 5 (Arc 1950) for Angola (according to Mungier).

Other candidates that use Clarke 1880 spheroid are these:

Point Noire (Congo)  MI datum No. 142

Mhast  (Angola offshore)

M’Poraloko  (Gabon)  MI datum No. 138

 

 

For your UTM 50N, you chose datum No. 7.

That’s Ascension Island, International (1924?) spheroid.

Good luck with that.

 

(Datum numbers here from Mapinfo 8.5 user’s guide.)

Dave Sherrod

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[Kiter Slack]

Thanks David. 

Unfortunately people keep sending me data without the datum but at least in these cases I did get the ellipsoid.

The UTM 32S data needed to land off Gabon so as you suggested 138 is the best guess

138

M'Poraloko

Gabon

Clarke 1880

and the UTM50N is in the Philippines so have select this one.

50

Luzon

Philippines (excluding Mindanao Island)

Clarke 1866

Obviously they are just best guesses as they could have used other datums.

At the moment I am just plotting 1:1m scale maps so ± a few hundred metres isn't an issue until they want to get into the detail.

Many thanks again David.

Cheers

Slack