KAP Files Help appreciated

[moseriw]

Pleasure and a little payback to the value OpenCPN gives me

[.Paul.]

Originally Posted by moseriw

Thank you for the input and the infos about CM93. I really thought they are accurate I have the list of lights - of course.

Just to mention
NW REF1
NE REF2
SE REF3
SW REF4

the howto at OpenCPN is incorrect. DTM is not a good solution as it moves rhe chart out of the border frame. So I will set the border to the chart's positions and experiment with the REF's to find the exact matches with real coordinates.

btw. If you set the border and REF's to the same coordinates and the chart does not match the frame... I measured the chart and difference in NM's built a percentage and resized the chart's pixels.

Moseriw,

The problem of the chart image and its border not matching when the DTM offsets are specified in the KAP header was fixed in OpenCPN 4.1.1317 (beta and release candidate). The OpenCPN Stable Release 4.2.0 that was released today includes this correction.

Paul

[moseriw]

Sailors I have a nice issue - or dangereous???

Relying on CM 93:

2654 Novigrad, Wellenbrecher, Kopf 45° 19,1' Blz. w./r./gn. 5 s 8/5/6 sm 7 m
HR 54 w. Turm mit Galerie (6 m) 13° 33,5' 1 + (4) s
w. 003° - 025°, r. 025° - - 058°,
w. 058° - - 117°, gn. 117° - 003°







Set Point exactly at lighthouse - maximum Zoom

Zooming out

[moseriw]

funny.. no comments on last post?

[HappySeagull]

Originally Posted by moseriw

funny.. no comments on last post?

well, I'll bite.
As to cm93, it uses several scales of charts. It's not unusual for any small scale charts to have an iffy accuracy . Remember what a similar-scale paper chart is like....If it covers an ocean, it's not going to pinpoint lighthouses or anything else. ( eg: Mercator flat plane distorts a sphere)
But I'd expect the largest scale (seen as you zoom in) should be the most accurate.

Add to the above: as I said, cm93 got its data per the lighthouses shorelines and rocks... somewhere.

Overall, there was lots of data that got incorporated into digital maps and charts from various sources. hereabouts, I think a shoreline may have originally come from airplane stereo pix made in the 20's ....interesting story- but it's in transition- Satellites radar and better sonar are taking it over.

blah blah ...anyways, Locally, YOU are a better judge than I am.
So, choose: Lightlist? cm93? angles from mountain peaks to points of land taken from an old chart drawn by Captain Cook?

[bcn]

An example for the cases Happy is mentioning (zooming in):

[CarCode]

Either the title of this thread is wrong or the comments are wrong. These are no KAP files (raster) but vector charts (ENC) shown here.

Gerhard

[HappySeagull]

Carcode ...the OP is attempting to calibrate a "kap" chart using cm93. Read back a ways...

[moseriw]

tks I am passing the Male Karte to official sureveyors. Maybe it is the chart datum. The yellow red waypoins indicate the positions as per List of Lights

[bcn]

Just for fun if you like:

there are 99 S-63/S-57 vector charts for Croatia.
If you interested in a special area you might check those and compare.

[HappySeagull]

Originally Posted by moseriw

tks I am passing the Male Karte to official sureveyors. Maybe it is the chart datum. The yellow red waypoins indicate the positions as per List of Lights

good for you. If you have an official up-to-date chart that you are sure is wrong, it does no harm to mention it to the HO.
A long while ago, a friend of mine noticed a rock only awash at low water that was missing and I wrote in about it....They replied that there was no rock- just the drying shore shown, but the next survey found the rock that is beyond the shore- maybe a bit of the shore that had crumbled off which is not so unlikely thereabouts, but stuff happens.

[moseriw]

well it will take some time until I get resonse from the geographic institute but I will stay on this thread until we can close it - satisfied.

[moseriw]

just a little update:
I checked Plic Paklena, Umag/Croatia in OpenCPN
List of Lights = 45° 26,5' N 13° 30,3' E
against CM93 (262° 113m) and NV-Digital HR1 (266° 121m) difference.

To make sure the NV-Charts are correct I checked the light with the nv-charts free software

Errors 3,7m N but 536m E

In spite of this I recommend to check every bloody professional chart for tolerances before one uses it - or what I try - to scan your own charts and to home in to the correct positions for yourself - if even possible.

[moseriw]

still waiting for replies of NV-Charts and the Institute.
Holding on.