CODEWITHSUNDEEP
shellcompassdegreesash
Baobab
Baobab

Reputation: 157

shell script to convert degrees to cardinal direction

Is there any way to port the following python function to an ash-based shell script?

#def degrees_to_cardinal(d):
        #dirs = ["N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE",
            #"S", "SSW", "SW", "WSW", "W", "WNW", "NW", "NNW"]
       # ix = int((d + 11.25)/22.5)
        #return dirs[ix % 16]

Essentially what I need is to convert a value corresponding to a direction (0-360 degrees) to its corresponding 16-point cardinal direction. degrees -> cardinal direction.

I could use a series of if elif elif... but that seems clumsy and inefficient.

Upvotes: 0

Views: 684

Answers (4)

Martin Gross
Martin Gross

Reputation: 1

This version works for me:

#!/bin/ash

awk -v deg="$1" '
  BEGIN {
    dirs[0]="N"  ; dirs[1]="NNO" ; dirs[2]="NO" ; dirs[3]="ONO"
    dirs[4]= "O" ; dirs[5]="OSO" ; dirs[6]="SO" ; dirs[7]="SSO"
    dirs[8]="S"  ; dirs[9]="SSW"; dirs[10]="SW"; dirs[11]="WSW"
    dirs[12]="W" ; dirs[13]="WNW"; dirs[14]="NW"; dirs[15]="NNW"
    dirs[16]="N"
   }
  END {
     ix = int((deg + 11.25)/22.5)
     print dirs[ix]
}' /dev/null

Upvotes: -1

shellter
shellter

Reputation: 37298

cat degs2dir
#!/bin/ash

awk -v deg="$1" '
  BEGIN {
    dirs[1]="N"  ; dirs[2]="NNE" ; dirs[3]="NE" ; dirs[4]="ENE"
    dirs[5]= "E" ; dirs[6]="ESE" ; dirs[7]="SE" ; dirs[8]="SSE"
    dirs[9]="S"  ; dirs[10]="SSW"; dirs[11]="SW"; dirs[12]="WSW"
    dirs[13]="W" ; dirs[14]="WNW"; dirs[15]="NW"; dirs[16]="NNW"
   }
  END {
     ix = int((deg + 11.25)/22.5)
     print dirs[ix]
}' /dev/null

chmod 755 degs2dir
degs2dir 237

#output
SW

IHTH

Upvotes: -1

PixelBlurb
PixelBlurb

Reputation: 58

Here's something that might suit your needs:

D=N..NNENE.ENEE..ESESE.SSES..SSWSW.WSWW..WNWNW.NNW
d=$((d*2))
n=${D:$(((d/45)*3)):3}
echo ${n//.*}

Where "d" is the degree value

Upvotes: 1

PixelBlurb
PixelBlurb

Reputation: 58

It must be said that bash has no real way of handling floating point numbers.

Of course, to get around this you can just multiply 360 by 5 or 10 and then modify the rest of the script accordingly.

Upvotes: 1

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