David Booth a �crit:

> Hi everyone,
>
> Hope a mapX question isn't too off-topic for MI-L...
>
> Does anyone have any tips for speeding up map redraws in mapX (I'm using
> V5).
>
> I'm developing a mapX application which uses a large seamless raster table
> as background mapping (20 or so TIFF images - Ordnance Survey Internet
> Street Mapping, for anyone in the UK who knows what that is).

We choosed to use a pyramidal format (ECW in our case) for raster.  Even
if you choose poor compression for a better image quality, this leads to
much better performances.  the performances are also independant of the
file size.  So we replaced some hundreds of tiff orthoimages by a unique
and quite large (2 Go) ecw file.  We made some tests and a rewrite tooks
now less than one second instead of 20 to 30 seconds when you zoom
out...

Ecw reading is included in MapX 5.0 as in MapBasic 7.0 (and you can
download a free plugin for older versions of MapInfo).
You can very quickly test if this will work for you :

Er Mapper has a free compressor that accept imput images up to 500 Mo.
- use it to transform directy your tiff images in ecw images in the same
directory, keeping also the same name before the extension.
- save the .tab files associated to the tiff images (one never knows...)
- edit them to replace ".tif" by ".ecw" in the image file names

Now you can test your mapX application since the seemless table points
to the .tab file, end will then use the ecw compressed images.

--
Michel Wurtz
MAAPAR/DGA/SDSI/CERIT/DIG



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