Raster to XYZ

Converts an Arc ASCII Raster to a vector point file.

Description

This script simple reads in an ASCII raster file (in Arc ASCII Format) and then outputs a CSV file in XYZ format with a point (row) for each grid cell.

This is handy for converting gridded DEMs to raw point data.

It is slow because most of the IO part of the code can not be vectorized, but it does the trick.

• Acknowledgements: This submission has inspired the following:; ascii2xyz
• MATLAB release: MATLAB 6.5 (R13)

[Wolfgang Schwanghart]

Actually a good idea, but somewhat poorly implemented. First, the file is a script and not a function what may cause that variables in your workspace are overwritten when executing. As the author noticed, the function is slow, yet it CAN be vectorized (see e.g. dlmwrite with the option append). But even if you don't vectorize speed can be significantly improved when preallocating an array where you write the data to (see the Mlint report).

I tried the script on an ascii file I have. The script told me that it worked. Yet, I had a look at the csv and it was empty but the header. But that was my fault, since I forgot that my ascii grid had no header. Hence, this is my stupidity. However, I would have been confronted with my stupidity earlier, if there had been error checking.

In summary: There are many improvements to make. The script is heavily commented which is very good. Hence, I avoid a rating here and hope to see an update of the file soon.