Nice work, Achim. Will start using it.
This is a great project which deserves to be thoroughly tested.
I don’t know whether the GFS weather model is completely broken for what is called low level cloud, or whether the Spanish Gramet site is broken, but that site never depicted low level cloud (basically the stuff you see on a nice day, base say 2000-3000ft, maybe 2000ft thick).
GRAMET charts look good on the screen in the office, but they are not so well suited to viewing in poor contrast environments (outdoors), and printing them is a huge waste of toner. I would suggest using – either everywhere, or as an alternative – a monochrome scheme with white background and different types of hashing to indicate clouds and terrain, for example:
One more feature present at Ogimet and lacking here is wind components along the route – either down below like at Ogimet, or next to the wind barbs (e.g. “R 2kt T 5kt” or “L 7kt H 3kt”). Actually, when I first saw an Autorouter GRAMET a few days ago, I mistook the temperature figures for headwind/tailwind, so I’d recommend to add a degree sign to make the diagram more self-explanatory.
Oops, I meant different types of hatching, of course 
I agree that areas of solid colour are a big problem for printing. They use up a fantastic amount of ink/toner. But you will merely be told to not print anything
But they can also render very slowly on some PDF readers. For example if you look at the Jepp terminal charts, most of them render near-instantly, but when you get to their VFR charts, they can take a number of seconds to render. It is possibly a PDF driver setting, but which one? The obvious print resolution settings apply to images within the PDF (e.g. jpegs) but not to areas of solid colour which presumably are generated using postscript area fill / graduated fill commands.
PDF print drivers do normally have a config option for printing colours as B&W.
The site also doesn’t resolve waypoints which exist in more than one place, which is very common
That is a tricky one, but presumably one could pick the nearest one to the previous one.
GRAMET charts look good on the screen in the office, but they are not so well suited to viewing in poor contrast environments (outdoors), and printing them is a huge waste of toner.
Do you really think this chart is one that you would want to print and take with you? I consider it to be useful for flight preparation but not so much inflight because it only shows the planned route so is not suitable for tactical weather avoidance. The sample image you posted looks like it was faxed to you by the met office in 1990 
Doing this B&W is certainly possible in the future.
One more feature present at Ogimet and lacking here is wind components along the route – either down below like at Ogimet, or next to the wind barbs (e.g. “R 2kt T 5kt” or “L 7kt H 3kt”).
Yes, we plan to add this in some form. We do not want to use a table like Ogimet because of the screen space it requires and are discussing where and how to place this information.
Actually, when I first saw an Autorouter GRAMET a few days ago, I mistook the temperature figures for headwind/tailwind, so I’d recommend to add a degree sign to make the diagram more self-explanatory.
Good point, we’ll a small degree symbol.
But they can also render very slowly on some PDF readers.
That depends entirely how the PDFs are generated. PDF is a format that allows both vector data and raster data to be mixed. Often, applications use an amazing number of vector commands to draw on the screen and historically (Windows) printing is the same as drawing on the screen. The PDF print driver will then take the millions of vector commands and store them in the file for execution by the reader. This can take very long. The GRAMETs are original vector images created using the Cairo library which can generate PDF, SVG and others. They are very small (ca. 40kb for a 600NM route) and render very fast on any PDF viewer I have seen.
The site also doesn’t resolve waypoints which exist in more than one place, which is very common
We’ll look into this. GRAMET is backed by our flight plan parsing engine and for obvious reasons, it doesn’t accept any sort of ambiguity. In the GRAMET case, an educated guess should be in the user’s interest though.
I don’t know whether the GFS weather model is completely broken for what is called low level cloud, or whether the Spanish Gramet site is broken, but that site never depicted low level cloud (basically the stuff you see on a nice day, base say 2000-3000ft, maybe 2000ft thick).
Ogimet is broken, I don’t have any other explanation. I think he makes one principal mistake: he does not depict 25% clouds and thereby gives an overly optimistic presentation. It used to be much better though but lately it gives me pictures that I can hardly explain by looking at the GFS data. GFS is very good, only the resolution (0.5 degrees lat/lon) is poor, the COSMO EU model has 2.7km.
In the GRAMET case, an educated guess should be in the user’s interest though.
Especially as you are generating a PDF anyway, so plotting the assumed route on the last page, with a map of Europe as a backdrop, would trap any issues in a very obvious way.
Do you really think this chart is one that you would want to print and take with you? I consider it to be useful for flight preparation but not so much inflight because it only shows the planned route so is not suitable for tactical weather avoidance. The sample image you posted looks like it was faxed to you by the met office in 1990
It’s not suited for tactical weather avoidance as in flying around thunderstorm cells, but may be useful when this avoidance is done vertically, which you won’t do in a fast jet but will often do in a spamcan. Also, in some rare cases you may be asked to show a proof you’ve done a preflight weather briefing, and I suspect the old-school types asking you will only be happy to see something that looks like a fax from 1990s
One more easy thing to implement would be accepting flight level changes like in FPL: EGKA KOK EBBR /N0120F080 EDDK, possibly with actual climb and descent profiles for the aircraft in question.
One more easy thing to implement would be accepting flight level changes
It already does that if you throw a full flight plan at it.
I don’t see it for the simple mode, the simple mode should be just that, simple.
