[Qgis-user] First time here

[Carlos Cerdán]

Hola Luciano:

Mi Inglés no es bueno, así que con (o sin) el permiso del foro van estas 
líneas en español:

Bienvenido a QGIS!!

Tengo a la mano un par tutoriales que preparé para unas prácticas con 
GRASS bajo QGIS 1.8 que creo te serán útiles.

Tutorial 1 : https://docs.google.com/open?id=0B7OCKS4ZyCTARTJNY3h6RWFYcFk

Tutorial 2 : https://docs.google.com/open?id=0B7OCKS4ZyCTAODFOSGd5cXRqNzQ


En GRASS hay dos módulos que se ajustan a tus necesidades:

v.to.rast.const : convertir vectorial a raster usando una constante

v.to.rast.attr : convertir vectorial a raster usando valores de su tabla 
de atributos

Además la calculadora gráfica de GRASS también te será muy útil.

Saludos desde Cajamarca - Perú


--------------------

My English is not good, so with (or without) the permission of the forum 
the above lines in Spanish:

Wellcome to QGIS!!

I have a couple of tutorials that I made for practices with GRASS under 
QGIS 1.8 that I think it will be useful for you

Tutorial 1 : https://docs.google.com/open?id=0B7OCKS4ZyCTARTJNY3h6RWFYcFk

Tutorial 2 : https://docs.google.com/open?id=0B7OCKS4ZyCTAODFOSGd5cXRqNzQ

GRASS have two tools that are for your request:

v.to.rast.const

v.to.rast.attr

Graphical calculator will be also useful for you.

Cheers from Cajamarca - Perú




El 29/09/12 15:16, Luciano La Sala escribió:
> Hello QGIS users!
>
> My name is Luciano and I am a wildlife researcher from Argentina. I am
> rather new to the world of QGIS, so I apologize in advance for any rather
> basic question.
>   
> I have several shapefiles of Argentina which I am supposed to use to make a
> risk map. These vector files include:
>
> 1- Country border (line)
> 2- Airports (points)
> 3- Rivers (lines)
> 4- Wetlands (polygons)
> 5- Roads (lines)
> 6- Poultry farms (points)
>    
> I rasterized each of the vector files and gave each the same, new size (3993
> hight and 2393 width) to fit the entire country.
>
> Then, on each of the six maps, cells should be made to take a value of 1 if
> risk factor is present (road, city, airport, wetland, and so on) and 0
> otherwise. All the rasters should then be combined into one unified map. It
> is my understanding that this unified map can be made using different
> approaches (e.g. addition, addition and weighting, pair-wise comparisons).
> In ArcView 3.2 this is done with "map calculator" of the "spatial analysis"
> extension. These procedures would give a map in raster format where color
> intensity of the cells is associated with the risk present in the area.
> Finally, one can apply a kernel smoothing to ease interpretation of the map.
>
>
> So at this point my questions are:
>
> 1) How do I assign values of 0 or 1 to pixels on each raster image? I
> believe I could use RasterCalc plugin, but I just can't find a way around
> this.
>      
> 2) Once the above step is solved, how do I combine all maps into one using
> one of the mentioned procedures (e.g. addition)?
>
> Thank you in advance.
>
> Luciano La Sala
> Centro de Estudios Cuantitativos en Sanidad Animal (CECSA) - CONICET
> Facultad de Ciencias Veterinarias - Casilda
> Universidad Nacional de Rosario
> Argentina
>
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-user

El 29/09/12 15:16, Luciano La Sala escribió:
> Hello QGIS users!
>
> My name is Luciano and I am a wildlife researcher from Argentina. I am
> rather new to the world of QGIS, so I apologize in advance for any rather
> basic question.
>   
> I have several shapefiles of Argentina which I am supposed to use to make a
> risk map. These vector files include:
>
> 1- Country border (line)
> 2- Airports (points)
> 3- Rivers (lines)
> 4- Wetlands (polygons)
> 5- Roads (lines)
> 6- Poultry farms (points)
>    
> I rasterized each of the vector files and gave each the same, new size (3993
> hight and 2393 width) to fit the entire country.
>
> Then, on each of the six maps, cells should be made to take a value of 1 if
> risk factor is present (road, city, airport, wetland, and so on) and 0
> otherwise. All the rasters should then be combined into one unified map. It
> is my understanding that this unified map can be made using different
> approaches (e.g. addition, addition and weighting, pair-wise comparisons).
> In ArcView 3.2 this is done with "map calculator" of the "spatial analysis"
> extension. These procedures would give a map in raster format where color
> intensity of the cells is associated with the risk present in the area.
> Finally, one can apply a kernel smoothing to ease interpretation of the map.
>
>
> So at this point my questions are:
>
> 1) How do I assign values of 0 or 1 to pixels on each raster image? I
> believe I could use RasterCalc plugin, but I just can't find a way around
> this.
>      
> 2) Once the above step is solved, how do I combine all maps into one using
> one of the mentioned procedures (e.g. addition)?
>
> Thank you in advance.
>
> Luciano La Sala
> Centro de Estudios Cuantitativos en Sanidad Animal (CECSA) - CONICET
> Facultad de Ciencias Veterinarias - Casilda
> Universidad Nacional de Rosario
> Argentina
>
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-user