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Old 07-03-2012, 01:51   #16
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Re: Raster Conversion - Help Needed Please

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Originally Posted by HappySeagull View Post
I'm starting to cry! It's like all the chicks got Avian Flu and were slaughtered...
Read some times ago that tears are good against depression....

And to repeat the suggestions from the Charts II: NGA - 2700 Charts thread (#1278) to have a look how to use the skills, methods, insights from the project to enable users to create and maintain their raster chart collections.
The project can count an my efforts if helpful and I'm sure that there are some more contributors here around.

Hubert
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Old 07-03-2012, 08:17   #17
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Re: Raster Conversion - Help Needed Please

I agree, but the things you all learned can result in awesome improvements and chart flexibility!
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Old 08-03-2012, 15:04   #18
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Re: Raster Conversion - Help Needed Please

The underlying tools used are all talked about on the OpenCPN site:

==> Chart Conversion | Official OpenCPN Homepage

The most custom work done for this project was the custom apps to allow people to more easily calibrate large numbers of charts, and the apps for tracking the progress.

This link (pulled from the page linked above) give a description of how to manually calibrate any image and create a .KAP chart from it.
==> MapCal Utilities

-dan
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Old 08-03-2012, 17:33   #19
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Re: Raster Conversion - Help Needed Please

Thank you Dan, those pages are very helpful and nicely detailed.

Just for example, I seem to have found a pdf of the Bahamas. Is it possible to convert to Tiff [palette] using Gimp. I also have a PDF Converter Pro which can create a Jpeg. which would then be converted to Gif. Then use the process you outline so clearly on your page to convert to BSB? I suppose I have to determine the lat long of four points somehow, to calibrate.

Incidentally, I enjoyed your Odd Boats pages, lots of chuckles. Odd Boats

I also had not connected the Free Nav Charts page as your's.
Inland Waters Resources

Thanks again. Rick
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Old 09-03-2012, 13:21   #20
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Re: Raster Conversion - Help Needed Please

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Originally Posted by rgleason View Post
Thank you Dan, those pages are very helpful and nicely detailed.

Just for example, I seem to have found a pdf of the Bahamas. Is it possible to convert to Tiff [palette] using Gimp. I also have a PDF Converter Pro which can create a Jpeg. which would then be converted to Gif. Then use the process you outline so clearly on your page to convert to BSB? I suppose I have to determine the lat long of four points somehow, to calibrate.

Incidentally, I enjoyed your Odd Boats pages, lots of chuckles. Odd Boats

I also had not connected the Free Nav Charts page as your's.
Inland Waters Resources

Thanks again. Rick
I would imagine you can convert to palette with gimp. I have gimp, but have not tired that. I tend to like command line solutions better, since I often write scripts to automate things. So, that's why I use ImageMagick convert instead. If you go to a .jpg, just make sure to use the highest quality to reduce your loss.

EDIT: You can experiment with the color depth (-127 in my examples) to reduce the image size. Just play with the numbers, get them as low as you can without degrading the colors in the image. If you have plenty of disk space, you may not care... END EDIT

Glad you like the other pages. The large part of the Odd Boats page was lifted from the ==> Nautical Oddities thread started by knottybuoyz in 2007 in the Off Topic section.

-dan
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Old 09-03-2012, 17:40   #21
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Re: Raster Conversion - Help Needed Please

Very helpful. I agree about batch process, for me I am just starting out with it.
I wish the NDA had a different approach re DNC. This world is getting smaller and smaller and pretty soon there will be more streamlined database I think.

Charts tailored for sailors with small boats and relatively shallow drafts. We are primarily interested in coastal features 50'deep and less. We are more interested monitoring changes in depth between 20-0. We need navigation aids, place names, current and tide. In deep areas >50' it might be nice to have some contours and general depths, but full details are not necessary.

It is too bad that in this digital age, we cannot have a system of charts that makes sense and works efficiently. Vector charts and ENC is a good move, -but companies similar to Simrad, provide generalized information on their plotters, leaving out harbor depths! (Chartplotters are slow computers. Why pay those prices for waterproof and daylight screens when we can get it on a smart phone.)

The digital chart guys/goverments/etc are doing the same thing Simrad does too, slice and dice information in small pieces and proprietary formats to drive profit.

If we all had depth/gps recorders (tide?) and uploaded to a central website across the world, (like MarineTraffic for AIS) and automatically recorded on a chart layer in standard format and on a common website, we'd have the world's main areas recorded in no time.

Chart technology: If our on board vector charts were recorded in sufficient detail for close scale, but had a generalization routine which simplified fractals and dropped out detail and information as one zooms out (writing it to a temporary file for reuse at say, 2-3 set scales) then we would have faster operation and smaller files. If the charts had only the information we need, (see above) they would be smaller.

If our software sensed areas which were of interest (center of the screen or following the cursor with some distance out) and filled in that detail appropriately, there would not be the same need for redraw and graphics speed.

It seems to me that the government and independent sellers are trying to compile comprehensive data we do not need (we aren't fishermen who really must have 3d) and insist on selling it in very small pieces. This is not the form or type of data I am willing to pay for!

It seems to me that an entire market is being missed, and it is an opportunity for someone to address culling the worldwide digital data available. Okay. -I've finished grumping.

I just ask one other question, with compiled data and multiple reversioning, translating, reconfiguring, joining, stiching, dropping data, simplifying data that can dropped, stitching, compressing, combining with other data, changing line weights and colors, etc is there a point at which copyrights lose meaning?

There are several links I find nteresting. Chart 51002 belpw it says "NOTE: Use the official, full scale NGA nautical chart for real navigation whenever possible. These are available from authorized NGA nautical chart sales agents. Screen captures of the on-line viewable charts available here do NOT fulfill chart carriage requirements for regulated commercial vessels under Titles 33 and 46 of the Code of Federal Regulations. "

I have not figured out how to save it, adobe seems to have developed greater security. The other related link is Region 5 - Western Africa, Mediterranean, Black Sea NGA Nautical Charts

The other ones are
" + theTitle + "
Informing Coastal and Marine Spatial Planning Efforts with Authoritative Data - In Action - Digital Coast
Multipurpose Marine Cadastre - NOAA Coastal Services Center

Is there any way we can get authorized to use DNC charts?
Could OpenCPN have a dll plugin for DNC?

These are probably pretty nutty questions, but I had to ask.
I apologize if this is considered off topic.

Rick
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Old 09-03-2012, 17:50   #22
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Re: Raster Conversion - Help Needed Please

PS actually that Bahama chart is a png.
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