Difference between revisions of "SequentialGrid"

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'''Q:''' How to generate a grid with sequential numbers?
  
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'''A:'''
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In a shell, first get number of rows and columns as environment variables:
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eval `g.region -g`
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(or just note the output of g.region -p and insert the relevant value at the appropriate place in the formulas below)
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Then use the variable 'rows' or 'cols' as follows:
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r.mapcalc "grid_seq = col() * $rows + row() - $rows"
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gives you a "vertical" sequence.
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r.mapcalc "grid_seq = row() * $cols + col() - $cols"
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gives you a "horizontal" sequence.
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[[Category:FAQ]]

Revision as of 06:10, 18 September 2012

Q: How to generate a grid with sequential numbers?

A:

In a shell, first get number of rows and columns as environment variables:

eval `g.region -g`

(or just note the output of g.region -p and insert the relevant value at the appropriate place in the formulas below)

Then use the variable 'rows' or 'cols' as follows:

r.mapcalc "grid_seq = col() * $rows + row() - $rows"

gives you a "vertical" sequence.

r.mapcalc "grid_seq = row() * $cols + col() - $cols"

gives you a "horizontal" sequence.