# How can I add this ruby code?
**URL:** https://discuss.elastic.co/t/how-can-i-add-this-ruby-code/152580
**Category:** Logstash
**Created:** [October 16, 2018, 2:41am UTC](https://discuss.elastic.co/t/how-can-i-add-this-ruby-code/152580 "2018-10-16T02:41:54Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Sjaak01](https://discuss.elastic.co/u/Sjaak01)
#### Post date: [October 16, 2018, 2:41am UTC](https://discuss.elastic.co/t/how-can-i-add-this-ruby-code/152580/1 "2018-10-16T02:41:54Z")
Hi,
I have GPS coordinates in DMS (degree minute second) that I need to convert to DD (decimal degrees) so they can be used in Elastic as geo points.
I already wrote I probably not very good filter to convert South and West values to negatives.
```
if [gps_lat] =~ /[SW]$/ {
mutate {
gsub => [
"gps_lat", "\D", " "
]
strip => ["gps_lat"]
#add_field => { "gps_lat2" => "-%{gps_lat}" }
```
Output:
11 22 33
Or
-11 22 33
Now I need a way to perform the following calculations to convert the values.
North/East
```auto
deg + (min / 60.0) + (sec / 3600.0)
```
South/West
```auto
deg - (min / 60.0) - (sec / 3600.0)
```
I found this ruby code online but simply copy/pasting it to a ruby code block doesn't work. No surprise. How can I get logstash to perform the calculation on the gps fields?
```auto
@to_decimal = lambda do |str|
deg, min, sec = str.split(" ").map(&:to_f)
if deg >= 0
output = deg + (min / 60.0) + (sec / 3600.0)
elsif deg < #HARD EARNED KNOWLEDGE HERE
output = deg - (min / 60.0) - (sec / 3600.0)
end
raise "something is wrong" if output.abs > 180
output
end
```
Source: [https://stackoverflow.com/questions/1774781/how-do-i-convert-coordinates-to-google-friendly-coordinates](https://stackoverflow.com/questions/1774781/how-do-i-convert-coordinates-to-google-friendly-coordinates)
---
### Author:  [@OphyTe](https://discuss.elastic.co/u/OphyTe)
#### Post date: [October 16, 2018, 8:55am UTC](https://discuss.elastic.co/t/how-can-i-add-this-ruby-code/152580/2 "2018-10-16T08:55:09Z")
Hi Sjaak,
Did you try to put it in a ruby file like explain in [the doc](https://www.elastic.co/guide/en/logstash/current/plugins-filters-ruby.html#_using_a_ruby_script_file) ?
For instance you set your ruby plugin like this :
```
filter {
ruby {
path => "/usr/share/logstash/dms2dd.rb"
script_params => { "gps_lat" => #{gps_lat2} }
}
}
```
And you create the `/usr/share/logstash/dms2dd.rb` ruby file :
```
# the value of `params` is the value of the hash passed to `script_params`
# in the logstash configuration
def register(params)
@str = params["gps_lat"]
end
# the filter method receives an event and must return a list of events.
# Dropping an event means not including it in the return array,
# while creating new ones only requires you to add a new instance of
# LogStash::Event to the returned array
def filter(event)
deg, min, sec = @str.split(" ").map(&:to_f)
if deg >= 0
output = deg + (min / 60.0) + (sec / 3600.0)
elsif deg < #HARD EARNED KNOWLEDGE HERE
output = deg - (min / 60.0) - (sec / 3600.0)
end
raise "something is wrong" if output.abs > 180
event.set("dd", output)
return [event]
end
```
You should have your converted coordinates in the "dd" field.
---
### Author:  [@Sjaak01](https://discuss.elastic.co/u/Sjaak01)
#### Post date: [October 17, 2018, 12:43am UTC](https://discuss.elastic.co/t/how-can-i-add-this-ruby-code/152580/3 "2018-10-17T00:43:58Z")
Thanks @OphyTe, but unfortunately I can't get it working.
```auto
script_params => { "gps_lat" => #{gps_lat2} }
```
Causes configuration errors. If I change it to "gps\_lat2" then the ruby filter fails with
> Could not process event: undefined method `/' for nil:NilClass
Looks like somehow it can't get the gps\_lat value? I tried looking at some examples and read the docs but there isn't much information about what is what.
I did manage to make a very ugly version myself by using a if conditional to check the location (N/E/S/W), then apply a grok filter to slice up the value in three fields, use a ruby calculation on each field, and finally a mutate to put it all back together.
It works but the whole thing is like 150 lines... Would much rather get it working through this .rb.
---
### Author:  [@OphyTe](https://discuss.elastic.co/u/OphyTe)
#### Post date: [October 17, 2018, 9:59am UTC](https://discuss.elastic.co/t/how-can-i-add-this-ruby-code/152580/4 "2018-10-17T09:59:03Z")
Hi Sjaak,
You're probably right, it should be `script_params => { "gps_lat" => gps_lat2 }`.
For the next issue, I'm not a ruby master and I'm really not comfortable with the first lines syntax of the code block you gave in your first message. I've just copied it . Have you tried something really simple like
```
def register(params)
@str = params["gps_lat"]
end
def filter(event)
puts "str = @str"
return [event]
end
```
And then if it works, try to put you logic in it ...
For the record I would have written it like this 😊 :
```
def register(params)
@str = params["gps_lat"]
end
def filter(event)
ddArray = @str.split(" ").map(&:to_f)
deg = ddArray[0]
min = ddArray[1]
sec = ddArray[2]
if deg >= 0
output = deg + (min / 60.0) + (sec / 3600.0)
else
output = deg - (min / 60.0) - (sec / 3600.0)
end
raise "something is wrong" if output.abs > 180
event.set("dd", output)
return [event]
end
```
---
### Author:  [@Sjaak01](https://discuss.elastic.co/u/Sjaak01)
#### Post date: [October 21, 2018, 11:33pm UTC](https://discuss.elastic.co/t/how-can-i-add-this-ruby-code/152580/5 "2018-10-21T23:33:10Z")
Thanks, I will try it out.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [November 18, 2018, 11:33pm UTC](https://discuss.elastic.co/t/how-can-i-add-this-ruby-code/152580/6 "2018-11-18T23:33:14Z")
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