# Difference between revisions of "SequentialGrid"

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+ | '''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. | ||

+ | |||

+ | |||

+ | [[Category:FAQ]] |

## Revision as of 05:10, 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.