[GRASS-user] Generating categorical int values from a string attribute for use with v.to.rast

[Helmut Kudrnovsky]

Damian Maddalena wrote
> I am trying to convert vector SSURGO soils data to a raster using 
> v.to.rast. The attribute I want to use for the conversion is a 
> categorical string describing soil type, so I need to generate int 
> categories before converting. I explored v.category for doing this, but 
> I'm not sure it's what I'm looking for. I want to assign all polygons 
> with the same soil description the same number. For example, output from 
> `v.db.select map=soils | head` is below.  I want to create a new 
> attribute based on "sm_soil_se" called "sm_soil_se_int" that is a 
> categorical int value for each string category. I don't care what the 
> numbers are, so long as each of the polygons with the same string value 
> have the same categorical int value. (I will assign the string values to 
> each int category using the "label_column" parameter.)
> 
> Is there an existing GRASS command that will do this? If not, should I 
> be using Python?
> 
> Thank  you!!
> 
> -Damian
> 
> cat|sm_mapunit|sm_mapun_1|sm_soil_se|sm_csr|rating
> 1|160|456713|"Xerorthents-Millsholm complex, 50 to 75 percent slopes"||10
> 2|TaE|455865|"Tierra loam, 15 to 30 percent slopes, MLRA 14"||40
> 3|CoF|455785|"Cut and fill land-Millsholm complex, 30 to 50 percent 
> slopes"||20
> 4|MeG|455829|"Millsholm loam, 20 to 60 percent slopes, moist, MLRA 15"||10
> 5|LeF|455816|"Los Gatos loam, 30 to 50 percent slopes"||20
> 6|GcF|455802|"Los Gatos loam, 30 to 50 percent slopes"||20
> 
> -- 
> “Science knows it doesn't know everything; otherwise, it'd stop." ~Dara
> O'Briain
> 
> _______________________________________________
> grass-user mailing list

> grass-user at .osgeo

> https://lists.osgeo.org/mailman/listinfo/grass-user

See

https://grass.osgeo.org/grass76/manuals/v.db.update.html



-----
best regards
Helmut
--
Sent from: http://osgeo-org.1560.x6.nabble.com/Grass-Users-f3884509.html