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Groups > comp.graphics.apps.gnuplot > #3296

Request for Direction in Creating a Gnuplot

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I want to create what's called an "intensity plot" in some programs, such as Matlab. I don't know what it's called in gnuplot terminology. By "intensity plot" I mean a black-and-white flat image (grayscale?) that is dark in some regions and light in others. I want to create the image from data in a text file that has three columns of numeric data. The first two columns represent X and Y coordinates. The third column is the Z (intensity) value. All data are decimal values (ie not integers). Would this be a 2D or 3D plot?

From what I've read so far 3D gnuplot data file format requires a blank line after each group of data that forms a column on the intensity image. It will be difficult for me to insert the blank lines so I don't want to do it unnecessarily. What is the blank line for anyway? Is it like a newline character in a text file?

I would also like to know if gnuplot processes data files line-by-line, or does it read and store the entire file prior to processing? My data file is about 1.2GB in size. I feel this size may be a problem if gnuplot has to store all the data in memory at once.

References to appropriate examples, documentation, or commands would be ideal.

All help/comments/recommendations are greatly appreciated.

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Request for Direction in Creating a Gnuplot km4hr <david.westbury@gmail.com> - 2016-04-15 16:44 -0700
  Re: Request for Direction in Creating a Gnuplot Gavin Buxton <gavinbuxton@gmail.com> - 2016-04-16 07:23 -0700
  Re: Request for Direction in Creating a Gnuplot Ethan A Merritt <EAMerritt@gmail.com> - 2016-04-16 11:32 -0700

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