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spatial_analysis:sp_intro [2010/04/20 09:54]
steko created
spatial_analysis:sp_intro [2018/08/04 00:01] (current)
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 ===== Importing data ===== ===== Importing data =====
  
-Using ''​rgdal''​ or ''​spgrass6''​ to import existing GIS data+Using ''​rgdal''​ or ''​spgrass6''​ to import existing GIS data is probably the easiest way to get started. Both packages can also be used to export the results of your analysis back to a GIS environment. 
 + 
 +An example using ''​rgdal''​ to import an ESRI Shapefile named ''​points.shp''​ located in the ''/​home/​steko/​gisdata/''​ directory. 
 + 
 +<code R> 
 +> library(rgdal) 
 +> points <- readOGR(dsn="/​home/​steko/​gisdata",​ layer="​points"​) 
 +OGR data source with driver: ESRI Shapefile  
 +Source: "/​home/​steko/​gisdata",​ layer: "​points"​ 
 +with 61 features and 6 fields 
 +Feature type: wkbPoint with 2 dimensions 
 +</​code>​ 
 + 
 +Let's have a look at the imported data. Note that the ''​points''​ object is a ''​SpatialPointsDataFrame''​. 
 +<code R> 
 +> str(points) 
 +Formal class '​SpatialPointsDataFrame'​ [package "​sp"​] with 5 slots 
 +  ..@ data       :'​data.frame':​ 61 obs. of  6 variables:​ 
 +  .. ..$ RECNUM ​ : Factor w/ 61 levels "​1","​10","​11",​..:​ 1 12 23 34 45 56 59 60 61 2 ... 
 +  .. ..$ NAME    : Factor w/ 61 levels "​001","​002","​003",​..:​ 1 2 3 4 5 6 7 8 9 10 ... 
 +  .. ..$ LAT     : Factor w/ 61 levels "​8023340.86","​8023775.89",​..:​ 19 5 10 9 13 16 17 20 22 31 ... 
 +  .. ..$ LON     : Factor w/ 60 levels "​715020.00","​715327.00",​..:​ 38 60 55 58 59 57 39 36 45 43 ... 
 +  .. ..$ ALTITUDE: Factor w/ 37 levels "​10","​-115","​16",​..:​ 2 30 4 37 23 9 21 33 10 25 ... 
 +  .. ..$ LONGNAME: Factor w/ 0 levels: NA NA NA NA NA NA NA NA NA NA ... 
 +  ..@ coords.nrs : num(0)  
 +  ..@ coords ​    : num [1:61, 1:2] 747843 749457 749235 749365 749397 ... 
 +  .. ..- attr(*, "​dimnames"​)=List of 2 
 +  .. .. ..$ : NULL 
 +  .. .. ..$ : chr [1:2] "​coords.x1"​ "​coords.x2"​ 
 +  ..@ bbox       : num [1:2, 1:2] 715020 8023341 749457 8072390 
 +  .. ..- attr(*, "​dimnames"​)=List of 2 
 +  .. .. ..$ : chr [1:2] "​coords.x1"​ "​coords.x2"​ 
 +  .. .. ..$ : chr [1:2] "​min"​ "​max"​ 
 +  ..@ proj4string:​Formal class '​CRS'​ [package "​sp"​] with 1 slots 
 +  .. .. ..@ projargs: chr NA 
 +</​code>​
spatial_analysis/sp_intro.txt · Last modified: 2018/08/04 00:01 (external edit)