Printing off approach plates on demand?

Greg Farris wrote:
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.

Ah, now I understand what you're getting at. The "zoom" feature in AutoCad
is not a photographic/geometric zoom, it's a scale change. It's like
looking at a terminal chart, a sectional, and a WAC of the same area. Some
things have been scaled (i.e. the distance between geographic features),
and some have not (the size of a VOR compass rose).

That's a much higher level concept than raster vs. vector graphics. In
AutoCad, the entire vector graphics representation is regenerated from
AutoCad's internal object model each time you change the scale.

Peter wrote:
Mark Hansen wrote:



In Europe, Jepp have to obtain the AIP (in the USA this is the airport
facility directory, I think) for each country, and pick the stuff out
of there, carefully checking if anything has changed since last time.

Jepp uses the AIP for most countries, not just Europe. For many
countries the only source for an instrument approach procedure is a
graphical presentation (in chart form) in the AIP.

In the United States, Jeppesen uses an FAA electronic rendition of the
8260 series forms, plus they obtain non-regulatory airport information
from several other sources (such as frequncies, identifiers, runway
lengths, etc.)

Maule Driver wrote:

Some years ago, the Gov charts began copying the briefing strip from
Jepp. Closed the gap a bit I hear. I've never used Jepp.

Jeppesen did not originate the briefing strip. It was a recommendation
of the Volpe resarach organization within the DOT:

http://www.volpe.dot.gov/

Roy Smith wrote:

Greg Farris wrote:


I love the Jepp advertisement - says something like "New Technology -
Same Approach" and it shows a paper approach plate and a tablet display
of the same plate. The problem is the paper one looks sharp and detailed,
while the tablet display, although readable, appears pixelated and grainy
by comparison!


This is a real technology problem. For all the wonderful advances in
display technology, we're still nowhere near the resolution available using
ink on paper. A high quality printing press on good paper can do 1000
lines per inch. The best LCD displays today are only about 100 dpi.

I recently replaced my old monochrome laser printer with a good color
laser printer. I use a bright, multipurpose paper recommended by HP.
The Jepp charts are awesome, and the paper is good enough I can print
charts on both sides, on 8.5 x 11 paper.

Trouble is, it is still a reflected light image. The lighting gets bad,
and the chart is difficult to read. Not so with electronic charts.

I don't believe your statement about electronic displays being limited
to 100 dpi is correct. The Jeppesen charts are in vector graphics
format and rescale to fit the "zoom."

In the Part 25 cockpit displays I have seen that are certified, the Jepp
charts are far more flexible and readable under all conditions than my
high-end printouts. And, they are all there all the time.

For flying a Cessna 182 though, my printouts are a quantum leap over
Jepp's paper I used a few years ago.

Roy Smith wrote:

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.


Trouble is you can't get vector-graphic PDF files of Jeppesen charts.

Roy Smith wrote:


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.

Those scans were terrible. I occasionally convert Jepp charts into
bitmaps then assemble them into a PDF. They are awesome and appear to
be vector graphics until you zoom in really close. But, each chart is
800 to 1 meg.

Peter wrote:

(Roy Smith) wrote


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.


In the 1980s I ran a project (in my then own business) to develop a
complete postscript rasteriser. It was big money in those days, for
printing etc.

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 you say about JV makes sense... vector graphics. Very compact.

I wonder if anybody has cracked their coverage codes

No one at Jepp things so.

Mark Hansen wrote:

On 05/10/06 01:39, Greg Farris wrote:


With the subscription you can reduce the window for potential errors, but
not remove it. After all, there can be a tower frequency change which didn't
make it into the current published charts, so even the subscription may be
out of date.


NACO will continue to print an incorrect chart again and again when a
temporary FDC NOTAM is in effect for the chart.

Jepp may or may not, depending on a judgment call at Jeppesen about the
probable duration of the FDC NOTAM.

Jeppesen got burned bad a few years ago so they will never print a
change in a missed approach procedure that is issued by a temporary FDC
NOTAM.

Permanent FDC NOTAMs are a different matter. Both NACO and Jeppesen
will always chart those, i.e. "amendment 2 changed to 2A."

wrote in message
oups.com

I'm new to this IFR stuff and I'm wondering if I can subscribe to Jepp
or some other service and print off approach plates and airport
diagrams at my liesure? Ideally log into a web site every month, see
if the plate changed, and if so, re-print it. Seems easy, so I
imagine its available... any links and costs would be a great help.

As others have mentioned, you can print NACO charts directly from the Fed.
Another option I use is Sporty's Chart Viewer.

http://sportys.com/pilotshop/pages/chartviewer.cfm

This runs me about $11/mo and gives me every approach in the US on a single
DVD. The charts look great on my Gateway CX200 Tablet, but I can obviously
print as many as I want. For a typical flight, I'll print the airport
diagrams, departures, arrivals and approaches I expect to use and the rest
are readily available on the Tablet's hard drive (or disc drive, if you're
so inclined).

--
John T
http://sage1solutions.com/TknoFlyer
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