Hi guys!

Anyone has an experience implementing an application that displays

the first TOP 100 biggest objects (e.g. parcels) per zoom level?

This is similar to what they do in WikiMapia. As you zoom in, more

and more details are shown?

ghelo.arboleda

namria, philippines

ghelobytes@yahoo.com

You need to know the area displayed in the current view and zoom level and clip overlapping objects. This means you can't do it in SQL only. You could generate a Geom of the current viewbox by program in a seperate drawing and have a query do the clipping, sorting and filtering of the TOP 100. But for the first step we need to know if this is an IMS application. If not there is the problem of a missing OnViewChanged event that could trigger the program compareable to the OnClick event. I'm not sure but I think I've requested this event before. In AV3 there is some OnUpdateWindow for this purpose.

i was wondering about this for a wms service (show different results at different zoom levels), and the only thing i thought of was to just request a different wms layer when i zoomed in. alternately though, is there any way in manifold to set zoom dependencies for different subsets of data in a single drawing?

Crap! i was hoping it could be done in SQL alone.

Luckily my project is a desktop application.

Will this approach on displaying objects (parcels) contribute

on faster display of maps? Displaying thousands of objects

at the same time (in my case) is very slow.

ghelo.arboleda

namria, philippines

ghelobytes@yahoo.com

Don't you work with objects linked from DBMS and are you aware of Rick's great gey AOI button for server side filtering?

this only limits the aoi, are you suggesting this could be modified to work with subsets of the data?

AOI is a server sided filter of only the objects touching the AOI, with Ricks Tool AOI it's the currently visible area. Link this into manifold and create a query like

SELECT TOP 100 ...., [Geom (I)] FROM [linked Drawing with AOI] ORDER BY [Area (I)]

Link a Drawing to this query in ThisProject. This should do the job, not tested. You need to push Rick's button each time you change the view.

@KlausDE

I am working with linked objects and no, I wasn't aware of Rick's AIO button.

Thanks for pointing this out. I'll give it a test.

ghelo.arboleda

namria, philippines

ghelobytes@yahoo.com