Hi Guys,
I must be missing something here.
I have 3 world maps, low res, medium res and hig res. I want the low res map visible at say soomLevel01-05, the med res map from Zoomlevel 06-12 and the high res one visible from ZoomLevel13-20.
In our previous system we controlled this by min and max scales for each layer, how does this work with ThinkGeo?
Regards
John
Hi Guys,
Problem solved. Needed to adjust the scales of the zoomlevelset and was not prepared for how slow the drawing of the high resolution worldmap is. Can run with the low and medium level maps but the high level one is just too slow to use. Investigations continue (and yes they are all indexed)
John
John,
If you are using RasterLayer, you just need to set the min(LowerThreshold) and max(UpperThreshold) scales for each layer like what you did in your previous system. For vector layer, just wonder what data source you are using? Shape file, MSSql2008 or some other types? And how many records do you have in your data source? With index enabled, all their speed should be very fast anyway.
Here talk more about the ZoomLevel system. A zoomlevel is a range, not a point. For example, let’s say ZoomLevel10.Scale equals to 100, ZoomLevel11.Scale equals to 200 and ZoomLevel12.Scale equals to 400, then if the current scale is within 150 (average of ZoomLevel10.Scale to ZoomLevel11.Scale) to 300 (average of ZoomLevel11.Scale to ZoomLevel12.Scale), it belongs to ZoomLevel11. Also when displaying the map in Desktop, we snap to the nearest zoomlevel which means if the current scale is between 150 to 300, we snap it to 200 which is the “standard” scale of ZoomLevel11. In this way there are only 20 possible scales which will be much easier for caching.
Let me know if you have any issues.
Thanks,
Ben
Hi Ben,
Thanks for the update on the ZoomLevel system, that kind of reinforces what I discovered yesterday.
The data we are working with is vector stuff from SHP files.
We have 3 SHP files:-
ABCWorldSmall - 2 Mbytes Index = 114k 1,764 records
ABCWord - 22 Mbytes Index = 1.5 Mbytes 26,939 records
ABCWorldLarge - 92 Mbytes Index = 11 Mbytes 180,685 records
These are somewhat specialised files as they are just the world coastlines in differing levels of detail. They do not contain country information just the coastlines basically split into 4 areas by the Panama Canal (North and South America) and the Suez Canal (Africa and NW Europe/Russia/Asia).
Done this way so we can have a clean world map, no country borders but a sharp single pixel line representing the coastline, with the land area in a slightly lighter colour, seel below
In the large map, apart from loads of islands, this results in 5 large single shape records representing the five large continental masses at a reasonably high resolution (WVS at full scale)
We have set the zoomlevels to 1-5 for the small 6-12 for the medium map and 13-20 for the big one.
In our previous system this displayed very quickly at whatever scale, in ThinkGeo things start grinding to a halt as you go from zoomlevel 15 onwards with zoomlevel 20 taking about 10 seconds to redraw. Incidentally indexing the big layer takes about 5 minutes on my machine.
I guess it must be struggling with the shear size of that one shape that represents the Asian continent.
Happy to send the files in if this helps…
Regards
John
John,
I think that will be great if you can send the data to us. Please contact support@thinkgeo.com and ask for a FTP uploading account, or it will be more convenient if you can send a link to me so I can download. Send it to support@thinkgeo.com and ask to forward to Ben if you want.
Thanks,
Ben
Hi Ben,
Email on it’s way to support.
TTFN
John
John,
I’ve got your data and as you required, I will keep the conversation private by sending email to you.
Thanks,
Ben
Hi Ben,
Thanks, when we get something that will help the other guys, we need to make sure it hits this thread.
Regards
John
Yes, John. We should do that when we have something. :)