topic Re: Flow Accumulation and Time in ArcGIS Spatial Analyst Questions

Flow Accumulation and Time

NicholasRossi — Thu, 07 Nov 2013 11:58:27 GMT

I am currently in hour 24 of a flow accumulation process. I have searched through a few forums regarding the issues of not having a status bar, wondering how long until it finishes, etc. A few people have mentioned the size of their files and I apologize but I am new and am not exactly sure which file/raster I should be considering for size. My flow direction raster has an uncompressed size of 2.6 GB, obviously if this is the size people were mentioning I have a big problem and will be here for a long time before the accumulation finishes. My arcmap document on the other hand is about 4 MB. My original DEM mosaic raster is also 2.6 GB. What component is the limiting size?

Any insight you can provide would be very appreciated.

Thank you

Re: Flow Accumulation and Time

SteveLynch — Thu, 07 Nov 2013 14:55:40 GMT

Wrt size of the raster, right click on the input raster, Properties->Source->Columns and Rows. This will tell you how many pixels are to be processed.
In the case of a MosaicDataset it is not that simple, easiest way to do it is to use one of SA's less complex tools to create an output from which to determine the number of pixels that'll be processed. You could simply use the Int tool and then look at the number of columns and rows of the output raster created by Int.
Or in your case you can look at the properties of your FlowDirection raster, and, how long did it take to get created?

You also need to state what version of ArcGIS you are using.

-Steve

Re: Flow Accumulation and Time

NicholasRossi — Thu, 07 Nov 2013 15:11:14 GMT

Hi Steve, thank you for the reply.

I am using ArcGIS 10.

The source raster is 32,412 x 21,612 for a total of 700,488,144 pixels. The FlowDirection raster took about a half an hour.