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I am _still_ working on a Python DOM parser for tpeg. I got so far and then realised that the minidom library which I have been using does not load the enumerated types which specify a great deal of the fields (like ‘severity’, sheesh). If I understand it correctly (there is very little help around on this stuff) it is because they are not defined inline to the tpeg file itself but are reached through a convoluted route through the DTD’s.

There is a solution to this which is to parse them out of their source file first and then do a text replacement for the corresponding codes in the target tpeg file but this solution is so horribly inelegant that I cannot bring myself to do it without at least trying to find an alternative.

I have had a suggestion about creating permalinks to region layers which I believe is doable so will be looking into this.

Google have updated their map API and apparently are ditching the use of ‘openInfoWindowXslt’ which my ‘createMarker’ function in gmaps.js uses. I need to look into this as I assume the new API will be made official sometime soon.

Firefox Compatibility Issues

Thanks everyone for comments on Firefox compatibility. Looks like most 0f the issues are to do with browser settings. In particular I received a mail from Joe Fuller from stumbleupon who had pointed out problems with displaying images. It turns out that the problem was the ‘Load Images’ setting on the Tools/Options dialog in Firefox. The ‘original website only’ checkbox will supress the loading of the icons so it needs to be deselected. Thanks to Joe for looking into that.

Things I am going to do:

– Build help page with a proper description that the various layers and icons mean.

– Release the python code for TPEG parser. This has been prompted by Tim Almonds posting to the backstage site with his mini parser for the M4 summary text. I started to add stuff to it then I thought ‘stuff it’ I will just rewrite the main parser for gTraffic to use the python DOM. The current code uses SAX and I wouldn’t subject the world to it.

So ‘why’ I hear you say. Well, the current design pulls _all_ the data from each TPEG entry. This means the the results can be ordered for severity and road and then written out as html, xml etc.

BBC Jam Cams as displayed on camera layers all appear to be down.

VMS Finally

The VMS (Variable Message Sign) data is finally up and working. I had to filter the data heavily to avoid sign overload. Basically what is shown is every ‘unique’ message for each road and lane. This is to avoid displaying the same message all the way up and down the motorway.

Some of the icons for the BBC data now reflect their ‘type’. Interesting to note the majority of the data is roadworks. Whether these are the same as the QMISS data I haven’t checked.

The site has been moved to my ISP’s new cgi server. This was fairly painless. I don’t know when they will yank the old machine out but I am hoping to have moved this blog as well by then.

You will notice the new scale control on the bottom left corner as well. Neat.

Future Developments

There has been little changes to the site since last week because I have been working furiously to try and map the QMISS Midas speed sensor data on the the map. This _still_ isn’t in a useful state but I have developed the filtering code which should let me finally plot the VMS motorway sign settings.

I am unhappy with the regional menu implementation and i have decided that the user should be presented with some sort of data when they enter the page initally. This will take the form of the most recent 50 entries or something like that. Anything but a blank map. The user can then choose regional traffic, regional transport from the pull down menu of datasets.

I have been kicking myself since seeing this. Why didn’t I find these when I went searching for traffic cams? There are some cameras in Belfast but they are unusable in this context. Nicely done anyway.

Frozen Events

Looks like the bbc have discontinued or altered the updating mechanism of the traffic and transport tpeg xml feeds. This is why there are still events hanging around from Jun 30th on the map. I guess I will have to do what I have been meaning to for ages and process the data on a region by region basis. These regional feeds seem to be kept up to date.

Have been playing around with GPolyline from the Google Maps API. Something may yet come of this.

Google Map API

I have been working to modify the site to use the new Google Map API. There are a few thing which aren’t quite there yet so I will leave the current site as it is until these are ironed out.

I quickly solved the problem of linking the icons on the panel to the map using arrays to hold the GMarker items and the associated XML block. You can find this here. My posting is under ‘ajr’. I thought my solution was quite good as it used the API elements only.

One of the new neat things I have noticed is that the map now offers detailed satellite images of London. This has made for some amusing moments as I attempt to match up where I placed camera icons with what the roads really look like. I never promised they were totally accurate and I see I am going to have to do a little (lot) of revision.

I have been having problems moving this blog to the new cgi server. If it goes belly up for a while then you know why!


I have added new content to site. The first thing to notice is that I have changed the icons. These have been altered as I plan to let the icons classify the type of event they are attached to. My initial attempts were a bit rubbish so I have left them blank on the traffic and transport pages.

There is a new page which is roadworks info as supplied from the QMISS xml feed here. I had a motorway VMS (Variable Message Sign) feed for the maps but I was looking at it over the weekend and there was some sort of fire on the M25, this caused every sign on the motorway to light up like a Christmas tree. Way way too much data for the browser which choked on it. I have some ideas about summarising the information.

Anyway, as it is the roadworks data is filtered on the following rules

– all severe events are passed
– only moderate events which have started are allowed
– only slight events which start on the current day are allowed.

This was the only way to keep the number of events down to a manageable size.

My isp in their infinite wisdom have decided to shut the current cgi server down and move every customer to a new one. I would like to say there will be no disruption but setting the redirection for the URL is bound to take some time to go through. I will try to do this overnight at some point during the week.

Comments and suggestions welcome.


Most of the BBC Jam Cams are back up again.

I am planning to add Roadworks and major road message sign values to the site at which point I will address outstanding issues with the rendering and layout.

The new content requires creation of two large parsers which though not difficult is hard graft especially when the sun is shining outside! I am slowly getting there. It doesn’t help that there is a dearth of free python development environments (I need a debugger to function). I have been using the eclipse plugin by activestate. The debugger is pretty flaky through and I have been falling back on the one bundled with the ERIC editor.

Summer solstice today which explains delays around the A303 which runs past Stonehenge in case anyone is interested.

Additional Content

The site as it stands has a few problems which need addressed.

– Doesn’t fit completely into IE window
– The google map control needs updating to the latest configuration. I have put in a fix for the problems earlier in the week but this is not the correct way to do it.
– As Dom pointed out in an earlier comment it is possible to use the Google panel directly in a manner which will resize to the screen properly. The benifit of this is that it is neater and whatever improvements Google make to this are inherited.

I am busy working on adding content to the page at the moment and will get to these soon.

The feed from the Cams seems to go up and down all the time. For instance, East London is feeding images now but Central London is mostly stuffed!

Check out Paul Wilsons clever mobile app.

Up again

Site up. I have added extra cams as you can see.

I have modifed the mapframe.html to load version 6 map. This seem to have cleared the problem for now.

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