Charts II: NGA - 2700 Charts

[recri]

Would it be hard to break the regions into subsets? Perhaps using the first two digits of the chart number.

So instead of reloading 619 charts for region 2 every time I refresh, I'd be getting roughly 70 charts for which ever region 2 subset I was working on.

[recri]

A new failure mode: 28300 - Bahia de Campeche portrays a land mass in the SE corner which will quilt over parts of Belize and the Caribbean if not PLY'ed off. So you need to look at adjacent maps quilted together to detect this.

[HappySeagull]

hmm.I see what you mean.They made the lump of Yucatan too big(and it covers coast North of Belize...leave a note,I guess.You can go back later when the Plying really gets going.It'll be easier with the chart now calibrated,at least....Or maybe we should call these:doable with rectangular inset plus the note?

[wdkester]

Help!
This is my first chart with an adjustment to lat/long.
Chart 28157 has the following info:

"World Geodetic System 1972 Datum"

and also -

"To the Navigator
Operational Datum Adjustment
To Position North American 1927 Datum Coodinates on This Chart
Add 06.55 seconds to latitude
Add 00.01 seconds to longitude"

What I did was -

"Corrects Chart to WGS72
.109 NORTHWARD
.0001 WESTWARD"

My reasoning was that if they had already corrected the chart why give the note.

Also, this is my first chart with "Indian Spring Low Water". I must be thought quite provencial, having only heard of "Indian Summer"

[HappySeagull]

David.Where's 28157?There isn't one.Anyways,it's Early Days with this stuff...you can always skip things you don't want to do.Leave the field blank,is all,so the kap won't get made yet.Or carry on,let it bake,download it and test it in OpenCPN.

It sounds like they are telling you how to match it with OLDER charts and OLDER Datum....say to transfer a fix from one to another chart.So you don't need to correct it at all.

[Meark56]

Maps (kap) of the Region 5 to download aren't correct. I do not want to undermine the work someone done, but there are lower quality and calibration problems as well. I deposite in the NGA project charts / maps incoming charts calibrated of 53086 to 53223 (63 charts). Here it suits you I can do more!

[recri]

David -

I agree with Happy. It sounds like some of the charts I found in west central america: they issued the chart on WGS, but there were enough NAD-1927 referenced charts still in circulation that they gave the correction to allow transfer of positions between charts.

We need to collect the annotation patterns we find and our collective interpretation of them. Anything that turns up on one chart will probably turn up on dozens more.

[HappySeagull]

Originally Posted by Meark56

Maps (kap) of the Region 5 to download aren't correct. I do not want to undermine the work someone done, but there are lower quality and calibration problems as well. I deposite in the NGA project charts / maps incoming charts calibrated of 53086 to 53223 (63 charts). Here it suits you I can do more!

Hi,Meark56.Can you give a specific example?There are many charts there.
This would help us.

[Meark56]

For example 53204.kap

[HappySeagull]

Meark.....53204 looks ok to me until you zoom in 3.2x.Am i missing something?



53205 was a bit odd.But I had redone it this morning...you picked a good area as I was tooling around there myself earlier!

[HappySeagull]

..but this is not pretty(the jagged line of latitude)



still worth having though.

[Meark56]

I explain more clearly
I downloaded 53204.kap and I think it was poorly cut.
the PLY were not placed correctly because we can see other retail charts.

[HappySeagull]

OH! Meark56,Yes,I see!
We have just started on all this and the online Calibration is still evolving.These kaps are still Beta for learning and testing...

So, to start we are considering charts like that to be "Doable but with insets".Later,the inset will be calibrated too.
Having the four corners done(as REFS will help calibrate the PLYS in the FINISHED kap but that will be later.

[cagney]

Originally Posted by Meark56

Maps (kap) of the Region 5 to download aren't correct. I do not want to undermine the work someone done, but there are lower quality and calibration problems as well. I deposite in the NGA project charts / maps incoming charts calibrated of 53086 to 53223 (63 charts). Here it suits you I can do more!

Please do not upload anything to "incoming" except for stitched together NGA chart picture files, as necessary.

You are free to use the pictures anyway you want, but as a project we are not interested in charts created to a "private" standard. Your kap file headers, for example, are far from complete.
.
What we need is all the basic information for each chart by using the web form. We are also happy to get information about "bad" charts etc, as in your latest posts.

The beauty of this approach is that this information later can be used to create set of charts to a uniform standard and a specific quality, to name one thing.
The kap files now available should be regarded as alpha testing samples, and treated as such.

Thomas

[Meark56]

I still upload a few cards on NGA charts project\incoming (Kap files) for region 5.