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Question from a model user:
I would like to run a spatial model for the entire Blue Mtns area at 90m gird size. That is about 17 million pixels. Is that too big? I get an import error on the stateclass grid.
To our knowledge the largest spatial run on ST-Sim was for 21 million cells by researchers at NCSU so I believe that your simulations with 17 million cells should be possible. What may be happening is that you are running out of memory. I know that the NCSU folks had access to powerful computers with more than 21GB of RAM. Can you be more specific about the error you are getting when you attempt to load your sclass raster? You will also need to use the 64bit version of the application for this size of landscape.
Check that all your spatial layers have the same row and column count and that your tiffs have attribute tables. If all that is in order, it might be a hardware limitation.
Todd
I found an error in the stateclass grid. When I fixed it, the model imported the stratum and stateclass grids just fine. So, I started a 5 year, 1 iteration test run using the 17 million pixel area. No error messages, but at 1 hour and 30 minutes, the model is still initializing and the resource monitor shows physical memory use at 97 percent of 16gb that I have in the machine. My guess is that the model is either not going to run or run extremely slowly given memory usage. I do need to run that large area, though, for a project. So, I may resample the input to 120m rather than 90m. That’s getting a bit large for pixel size, given the treatment scenario. So…any recommendations on a PC configuration that would run this model? And, does the model require Window 7? Most new machines with 32 gb of RAM come with Windows 8.
We have not tested ST-Sim on Windows 8 but there is no fundamental reason why it should not work. ST-Sim requires the .Net Framework 4.0 which should come with the Windows 8 OS.
We are running 21 million cells, and our machine is using ~18-21 GB of memory. For 40 time steps, it takes about 24-27 hours. Several of those hours are spent initlializing, so I’m not surprised about it taking a while to initialize on your machine. We are using spatial multipliers for many transitions, as well as transition targets, so that may affect run times and/or memory some too. I’d be happy to talk with you more about our experience and/or try to run your model with your inputs on my machine to test memory usage if that would help. My machine has 24 GB memory.
Jen Costanza
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