Skewed Transverse Mercator Charts

[cagney]

Anyone know of any skewed Transverse Mercator BSB charts?
A sample is needed for bug FS#1042.
Dave has pushed a fix for Mercator charts with SK=0 to Git.
This patch is working just fine, but it would be good if Tmercs could be handled as well. A possible solution is brewing but testing is needed.

Thomas

[houlejm]

You mean one like this:

KNP/SC=40000,GD=NAD83,PR=MERCATOR,PP=-40.1,PI=2.000,SP=,SK=238.9597222
TA=328.9597222,UN=FEET,SD=MEAN LOWER LOW WATER,DX=4.00,DY=4.00


Or like that:

KNP/SC=30000,GD=NAD83,PR=MERCATOR
PP=45.466667,PI=2.000000,SP=,SK=329.000000,TA=90.0 00000
UN=METRES,SD=LOW WATER DATUM,DX=3.000000,DY=3.000000

The first is NOAA chart 12324_7

The second I can send a sample.

Jean-Marie

[sailorF54]

Some official NZ test BSB Transverse Mercator Charts have
SK=360.0000
e.g. NZ511302.KAP
in
http://www.linz.govt.nz/sites/defaul.../BSB_NZTDS.zip


I am not sure this can help...

[cagney]

Originally Posted by houlejm

You mean one like this:

KNP/SC=40000,GD=NAD83,PR=MERCATOR,PP=-40.1,PI=2.000,SP=,SK=238.9597222
TA=328.9597222,UN=FEET,SD=MEAN LOWER LOW WATER,DX=4.00,DY=4.00


Or like that:

KNP/SC=30000,GD=NAD83,PR=MERCATOR
PP=45.466667,PI=2.000000,SP=,SK=329.000000,TA=90.0 00000
UN=METRES,SD=LOW WATER DATUM,DX=3.000000,DY=3.000000

The first is NOAA chart 12324_7

The second I can send a sample.

Jean-Marie

@houlejm & sailorF54

Neither.
It should be an official chart where
PR=TRANSVERSE MERCATOR
And
SK is not equal to "0" or "360"

Also

PR=UNIVERSAL TRANSVERSE MERCATOR
or
PR=TM
are also of interest.

Thanks for trying to help!

Thomas

[houlejm]

Originally Posted by cagney

@houlejm & sailorF54

Neither.
It should be an official chart where
PR=TRANSVERSE MERCATOR
And
SK is not equal to "0" or "360"

Also

PR=UNIVERSAL TRANSVERSE MERCATOR
or
PR=TM
are also of interest.

Thanks for trying to help!

Thomas

Thomas

Would not a chart with PR=MERCATOR and TA=90 be a transverse mercator chart

and

PR=MERCATOR and TA=328.9597222 be an oblique mercator chart

Jean-Marie

[cagney]

Originally Posted by houlejm

Thomas

Would not a chart with PR=MERCATOR and TA=90 be a transverse mercator chart

and

PR=MERCATOR and TA=328.9597222 be an oblique mercator chart

Jean-Marie

No!
PR fully describes the chart projection. TA is just the "text angle".
What you are reading now has a TA of 90.
Thomas

[cagney]

The Swedes used to publish (at least) two skewed Tmercs. Charts #1352 and #1353 but.... The charts were reissued as Mercator last spring. Anyone with access to the older version?

Thomas