Printing off approach plates on demand?

John R. Copeland wrote:
More specifically, Jepp plates are vector graphics, not raster images.
They are rendered into a raster image only at time of display,
so lines and edges won't appear fuzzy at high zoom levels.
That means each displayable image is constructed to the full resolution
of your display device only *after* you select a subsection of the chart,
such as the chart header, or the profile view, etc. for display.
That uses a little extra real-time image-processing computation,
but the result is an immensely better image than PDFs give us.

PDF is inherently vector graphics too (they *can* contain raster
scanned images, but the approach plates are vector). I just opened up
the HPN ILS-16 plate in Adobe Reader and zoomed in to 6400%. No
jaggies.

PDF is pretty much just PostScript with a few minor restrictions and
packaged up nicely in a standard file format. If you zoom in to about
800% on some of the standard symbols (vortac, displaced threshold) on
the charts, you can even see some classic PostScript coding errors
where they don't handle mitre clipping properly at the corners of
polygons. PostScript has built-in mechanisms to handle these (ahem)
corner cases, but whoever did coded up the postscript driver didn't do
it right.

"Roy Smith" wrote in message ...
John R. Copeland wrote:

That uses a little extra real-time image-processing computation,
but the result is an immensely better image than PDFs give us.

PDF is inherently vector graphics too (they *can* contain raster
scanned images, but the approach plates are vector). I just opened up
the HPN ILS-16 plate in Adobe Reader and zoomed in to 6400%. No
jaggies.


Thanks, Roy. I didn't really know how PDFs worked internally.
My subjective impression has always been that PDFs are a little fuzzy
in ALL sizes.
PDFs on my 640x480 PDA are especially objectionable.
Probably the Adobe Reader software in my PDA is incompetent.
It may have been designed for QVGA resolution instead of VGA.

I do a lot of work with AutoCad, which of course is a vector graphic
application, and you can zoom to your heart's content. When I need to
deliver content to those who cannot read AutoCad files, I often print to
PDF, but the limitations are severe - to the point of rendering the
content unreadable - that is unreadable to a sufficient and necessary
level of detail.

All PDF's are not created equal either.
Download some charts from Airnav and the same charts from AOPA, and you
will have two different file sizes, and a very notable difference in
resolution (the Airnav being far better).

GF

On 5/10/2006 2:51 PM, wrote the following:
Those Flightprep folks certainly seem to have a good system with the
GPS, WX, and Plates complete with the computer. Just plug it in and
go.

Yes. When start it up it even calls and gets all the METARs (assuming
you have an open internet connection) and displays them as color coded
dots on the map so you can see current conditions on your route of
flight as you plan it. Its birth was as a DUATS interface, so it is
very strong on accessing internet resources as you do your planning.

HOw was your experience with this system.

It is very solid in terms of crashes. IMHO there is still some
interface tuning needed in the in-flight readability area but I think
it's at the head of the class already with big easy-to-hit buttons and
the very slick architecture of their page system. I do not have the
XM weather so can't comment on that specifically.

It is great fun to watch your little airplane on an approach plate or
a runway diagram. It also records the flight by default, so you can
look at practice approaches, holds, etc. after the fact and see how
you did.

Does the computer run
windows? Can i use it for something other than aviation stuff (ie:
play a DVD)?

Yes. Yes. I am using an HP TC1100. The display is marginal in
bright light but that is not the fault of the application. The Motion
Computing boxes with the View Anywhere display are the hot ticket.
FlightPrep sells the LS800, which is a better size too. The TC1100 is
a tad big. I am waiting for the 1024 x 768 version of the LS800 and
then I will snap for it together with two docks. One for home and one
for our lake place, where I have full sized monitors and keyboards
plus other hardware connected. It will then be my only computer, used
for everything, just as the TC1100 is now.

HTH

In a previous article, "John R. Copeland" said:
"Roy Smith" wrote in message
...
PDF is inherently vector graphics too (they *can* contain raster
scanned images, but the approach plates are vector). I just opened up
the HPN ILS-16 plate in Adobe Reader and zoomed in to 6400%. No
jaggies.
Thanks, Roy. I didn't really know how PDFs worked internally.
My subjective impression has always been that PDFs are a little fuzzy
in ALL sizes.

Depends where you get the plates from. For a long time, various web sites
had approach plates that they'd scanned themselves, where the PDF
contained a raster image. But then NACO released their own PDFs, where
the plates are in vector format and eminently scalable.

I believe some web sites are still doing the scanned raster ones.

--
Paul Tomblin http://xcski.com/blogs/pt/
The Write Many, Read Never drive. For those people that don't know
their system has a /dev/null already.
-- Rik Steenwinkel, singing the praises of 8mm Exabytes

Peter wrote:
I am amazed Adobe don't do the corners right, given they invented and
specified the format. They should have *the* definitive rasteriser for
it.

What makes you think Adobe did anything wrong? I think whoever wrote the
postscript driver for the NOS/FAA/whatever folks didn't generate the
correct postscript. Looks like they neglected to do a "closepath" at the
appropriate places.

In article ,
Greg Farris wrote:

I do a lot of work with AutoCad, which of course is a vector graphic
application, and you can zoom to your heart's content. When I need to
deliver content to those who cannot read AutoCad files, I often print to
PDF, but the limitations are severe - to the point of rendering the
content unreadable - that is unreadable to a sufficient and necessary
level of detail.

If the PDF files are unreadable, then I'd say AutoCad isn't very smart
about how it generates PDFs. Or, more likely, it depends on some default
system-supplied print driver to generate them, and that does a bad job.

Done properly, PDF files should be just as zoomable as the AutoCad
originals.

In article ,
(Paul Tomblin) wrote:

Depends where you get the plates from. For a long time, various web sites
had approach plates that they'd scanned themselves, where the PDF
contained a raster image. But then NACO released their own PDFs, where
the plates are in vector format and eminently scalable.

Right, the scanned ones were horrible. Anybody who's still scanning
printed plates just doesn't get it. And anybody who's still using scanned
plates doesn't get it either.

One can abuse PDF just like one can abuse anything.

In article ,
says...

If the PDF files are unreadable, then I'd say AutoCad isn't very smart
about how it generates PDFs. Or, more likely, it depends on some default
system-supplied print driver to generate them, and that does a bad job.



You're probably right about that - It's not AutoCad that does that, it's
just printed using Adobe's Acrobat Distiller. I'd pay to have a PDF format I
could print to with even 1/10 the zoomability of AutoCad.

In article ,
says...


Done properly, PDF files should be just as zoomable as the AutoCad
originals.

What happens when you create a pdf from an AutoCad drawing, using Adobe's
"distiller" is not the same as the scanned raster images we're talking about
- it's more that line thicknesses do not scale correctly with your zoom
factor. If you zoom 1000% on your AutoCad drawing, simple lines are still one
pixel in width. You can see all the detail you want. If you create a pdf from
the same drawing, then zoom 1000%, you do not have a line thickness of 1000
pixels (fortunately) but it will be much more than one pixel - say 10 or
so. This puts real limits on the useful zoomability.

GF