Help w/ pyramids

[AlexBullen1]

I have a mosaic raster aerial image that is about 300 mb and covers about 6 square miles. I'd like to better set up pyramids to make loading time & scrolling time faster.

I've accepted the default pyramids, but the image loads about 5x slower than the basemap does even though the image is on my local machine.

What pyramid settings should I be looking into to decrease this processing time?

Thanks, I'm new to adjusting pyramid settings.

[ModyBuchbinder]

There is very limited setting you can do with the pyramids.

Most of the setting will change the time to build the pyramids but not to use them.

What is the format of the basic raster?

Sometime the pyramids is built in a different format and that is why they are slower.

[GordonSumerling]

Alex,

Firstly the Basemaps is a cache and it will load faster as it only loads the piece of image it requires at the resolution it requires.

Secondly, if your image is a large single image with pyramids then it will be slower to load as it has to load the entire image before it displays. If it is a large JP2 or MRSID then this would be slower than a Tiff.

I would recommend that you create a mosaic dataset in a file geodatabase and then add your image to the mosaic dataset. Creating overviews will apply a secondary pyramid over the image and improve performance. It will not be close to the cache speed but will be better than the single image by itself.

Cheers

Gordon

[AlexBullen1]

Thanks. I followed your instructions and it is faster than before. Still pretty slow overall - when I'm zoomed in to view individual neighborhood streets, and I move the image, it takes about 20 seconds to load each time - but it is better.

[JakeSkinner]

One more thing you can do to improve performance is to 'Accelerate' the mosaic dataset:

Accelerated raster rendering—Help | ArcGIS for Desktop

[AlexBullen1]

This is a nice feature because it lets me scroll around the image, and it loads while I scroll. Without acceleration, I move the image and ArcMap sort of 'freezes' while it loads the image. Definitely an improvement - I can at least try to get to where I want to view as the image loads - and it brought the load time down to about 15 seconds.

[CodyBenkelman]

Alex

It might be worth reviewing a few basics, although perhaps this is obvious -

The pyramids only speed up display when you are viewing at reduced resolution.  If you are seeing slow performance only when zoomed in to full resolution, it is the source file format that is slowing you down and pyramids won't help [but acceleration will - thanks Jake].  

You don't mention what format you have for the original file.  Some versions of JP2 can be really slow, and JPG is slow for very large images because the software has to read the entire file even if you are zoomed into a small subset.

If you are seeing poor performance at ALL zoom levels, then there is some other problem slowing you down.  15-20 seconds to refresh the screen when panning is definitely too slow.

If I'm correct that it's the full res source image that is slow, I would recommend rewriting the entire file using CopyRaster.   This may not be feasible if you have terabytes of data, but for one 300 MB file it should be pretty quick.  If you do that, I'd recommend saving as TIFF format.

Note re: Pyramids I would recommend you select bilinear interpolation resampling, not the default of nearest neighbor, to give you better quality images at reduced resolution.

Cody B