[GRASSLIST:1123] RE: [GRASS-user] GIS-> GRASS translation page up and running

[Hamish]

Jonathan Greenberg wrote:

> Quick wiki question: I'm trying to fill out the ARC GRID
> operator vs. r.mapcalc section, and one of the operators is "||"
> ("or"), which is also the command for "next cell" in wiki-table lingo.
> How do I get the table to NOT make a new cell and instead display the
> text "||" (no quotes) in a cell?

use HTML codes,

if( a || b )

see http://www.ascii.cl/htmlcodes.htm


> Note that for ARC-INFO commands I'm using ESRI's variable syntax
> copied directly from the ARC/INFO help manual. It would be useful to
> keep up this practice for all other ARC-INFO commands.

be very careful not to cut and paste any ESRI copyrighted material into
the Wiki.

> Some indication whether the external GIS command can be replicated
> "perfectly" by GRASS or if there are major differences
> between the two?  

I think in almost all cases it should be assumed the output will be
slightly different between implementations.


> [...] For instance, how can we solve the z_factor discrepancy -- how
> do I multiply a GRASS vector column by a fixed value?
> This would remove that discrepancy between the ARC and GRASS.

If I understand correctly, you can do that directly in the [v.]db.select
SQL statement.

http://grass.ibiblio.org/grass61/manuals/html61_user/sql.html


Hamish