scanned charts v photo

michael_99

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20 Feb 2005
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Is there any difference between a scanned chart and digital photo of a chart.
A digital photo would be much faster to do.
Also, is 40GB HD big enough. I'm about to buy a laptop.
 

SteveGorst

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A scanned chart would have a much higher resolution than a photo. This means that you will be able to zoom into the images a lot more on the screen before the picture starts to break up.

In order to save a lot of stitching you would be better with an A3 scanner or larger if you can access one.

A 40 Gb hard drive is pretty much entry level nowadays but will be plenty big enough for scanning charts. Try to get a dvd burner as well so that you can archive them if necessary.
 
G

Guest

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A scan has infinitely (well, almost) better resolution. Even with a professional level digital camera, you'll be squinting at the detail when it's blown up.

Even if you managed to get the chart readable with a digi camera, the lens will distort the perspective of the chart. so that distances and bearings will be considerably different in the corners from the centre! You'll also have other distortions if the camera back isn't 100% on a parallel plane to the chart. etc. etc. etc.

No, stick with scanning them.

40GB should be fine. I haven't used charting software, but assume that the images must be used in a compressed format, like JPEG. When you are scanning them, make sure that they are not saved as TIFFs (because the file size would be huge - I doubt that your software requires this), and play with resolution (about 200dpi should be about right).
 
G

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Little tricks ...

Before scanning .... make reference crosses for pasting scans back together .... second at regular intervals over chart write Lat / long next to line intersections so that when calibrating - you don't have to keep scrolling to edge to see lat / long scale

Also it is not necessary to stitch back together all the chart ... leave it in 2 or 3 sections - the software will jump from one chartlet to the next as boat moves, just make sure you have reasonable overlap ....
 
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