[talk-au] New Lowzoom

[Brent Easton]

Liz,

The lowzoom mechanism described below is in the process of being superceded by an improved version for zoom levels 8-11 that displays town and city names in a much better fashion, as well as more detail in the roads displayed.

The new version is considerably more complex. Stage 1 requires that a special layer be created that contains just the town and city names for zoom levels 8-11. 

Stage 2 requires that all 256 z12 tiles in a z8 tile have been 'recently' rendered by the new 'Poynton' client. This client creates a special 'captionless' layer that is basically the Zoom level 12 tile with no captions.

The final stage involves running a new lowzoom process that downloads the 256 captionless z12 tiles in a z8 area from stage 2, plus the special caption tiles created in stage 1 and merges them into the new lowzoom tiles.

About a week ago, I did stage 1 and created all of the caption tiles for all of Australia.

I then went on and ran stage 3 for much of SE Australia without realising the significance of Stage 2. Thus you can see the results where much of the lowzoom stuff is missing bits where the captionless Z12 tiles have not yet been created. Some tiles look great, som look terrible.

What happens next?

1. I ran a dummy lowzoom over all of Australia that has added every single missing z12 tile to the low  priority re-render queue. At the current rate of rendering, these are due to be finished in about 2 weeks. I will then start running lowzoom for all of Australia.

2. In the meantime, if you want to see a particular lowzoom Z8 tile, you need to manually scroll around using informationfreeway.org and display the 'captionless' layer. Then, manually request a re-render for any tiles that are missing. This will bump that tile up to the high priority queue and should be done within the hour. When all of the captionless tiles are done, email me the co-ords and I will run a lowzoom for it.

Hope this makes sense! Feel free to ask questions.

Regards,
Brent.


>Zoom to level 6 on informationfreeway and ctrl click on where you want to 
>render, this will tell you the level 6 tile co-ordinates. e.g. Canberra
>and 
>Sydney are in the 58 38 tile. 
>Change down to the tools/lowzoom directory and run "perl lowzoom.pl 58 38
>6 
>12" 
>And it 'should' just run. The lowzoom script needs image-magick installed. 
>lowzoom doesn't do an upload, it just copies the generated tiles into your 
>tilesathome tmp directory, so after it finishes running, go back to your 
>tilesaathome dir and run "perl tilesgen.pl upload"