Analogue teletext weather maps

This may seem like a silly question, and probably a bit old fashioned now the majority of us use digital text - but I've been wondering, how are the weather maps on analogue teletext created?

I'd be particularly interested to find out how Ceefax's are made, does someone have to sit there turning each individual square the correct colour, or do they use a system where they can highlight certain areas of the UK and turn it to the right colour?

My goodness, you really want to know don't you!?!!!

I would imagine so, hence he started this thread.

I suspect the maps were a development using the BBC Micro, I don't think they existed before that. Afterall the default character set of the BBC Micro was the Ceefax character set. I played with mine over time and generated an equivalent UK map, it really was simple to change the relevant characters in the set. using background and foreground colouring.

Wouldn't surprise me to see the current maps produced using some form of emulator of the BBC Micro.

It wasn't the default mode of the BBC, Mode 7 was the Viewdata/Teletext mode. IIRC Mode 3 was the default.

At school we had a 'viewdata' programme which effectively allowed us to create teletext pages on our BBC Model Bs. The graphics work on a blocks the size of a character, split up into 6 ( 2 columns of 3), you chose which of the 6 you wanted to make various shapes. There were also 'Hold' and background colour commands so you could have 4 out of the 6 in blue and the other 2 in red. Before these were introduced you needed a blank square to change colour so maps looked like this: http://teletext.mb21.co.uk/gallery/ceefax/ceefax-181-19780717.jpg

It's all a bit cumbersome compared to the drawing packages we know today

As for how they edit them now, i'd have thought that they'd use special teletext design software on a PC, it'd be WYSIWYG rather than having to work out the graphics yourself

There's instructions to a teletext editor here: http://www.heyrick.co.uk/software/ttx/ttxeug.html (which explains the 6-block graphics better than I can!)

This is incorrect. Mode 7 (teletext mode) was the default for the BBC Micro.



Analogue teletext services such as Ceefax are produced using PC-based applications.

AFAIK, Ceefax and Teletext UK use Sysmedia software. The software can be quite sophisticated. The Sysmedia set-up at RTE in Dublin allows the station to produce content for various platforms - analogue text, the web, WAP, and digital terrestrial teletext.

Is this true though? Are digital teletext users in the majority?

Personally, I still prefer the analogue text service. Ceefax is faster, uses a clearer font, and is much easier to navigate than the digital text service. Digital teletext is painfully slow. Also, a single page on Ceefax can easily become two or three pages on digital teletext.

Why do they insist on having the TV picture displayed in a window, taking up a large portion of the screen? Ditch the TV window - make the font larger, and get more text on to a single screen, and cut out this business of having to press the arrow key to read the next bloody paragraph.

Mode 7 was the default for the models up to the BBC Master Micro. From then on you could change it with *configure mode .

The BBC Micro was pretty much the first machine I did any real programing on. The worrying thing is I can remember most of the teletext control codes and the part number of the Teletext IC (SAA5050) from 20 odd years ago, yet I can't remember the number for SCAR from last Friday.

As others have said, Mode 7 was default as it gave you the best 40 column display (8 colours available which no ASCII mode could do without dropping to 20 columns, aswell as double height text and blinking in hardware) whilst using only 1K of video RAM. The downside was that you lost your bitmapped display so you couldn't do proper graphics or create your own characters.

Mode 3, incidentally was 640x200 2 colour mode, also giving you an 80x25 text display, but this chewed up a whopping 16K of video RAM and so wasn't for the feint hearted. 80 column text was also illegible unless you had a decent RGB monitor, if mode 3 was default you'd get serious eyestrain!

Hmmm I think it was, I remember that the F keys would change the text colour (and impressing my parents with that on a demo model in a shop)

The function keys were also programmable, using the *KEY command.

It was an excellent machine for its time.

Ho ho. Me too.

My mum and dad rewarded my apparent prowess with an Acorn Electron computer on my birthday (the BBC Micro's poor relation).

Available for a nominal sum for anyone who wants to re-create some cludgy old graphics.