Getting GPS metadata from a picture with Paperclip

Question

I have a question about Paperclip. Many modern cameras and phones add GPS metadata to a photo when taken:

geotagging

Users of my Rails app can upload photos and manually add the location data to them. However, this sucks as users don't want to enter that: they want it to be there automatically.

Can, and how can I get GPS metadata from a photo (always JPEG) with Paperclip and Ruby on Rails? Can it be done with Paperclip or do I need another gem?

Arnaud Leymet · Accepted Answer · 2011-02-17T10:37:48.757

18

What you need is being able to extract EXIF information from the picture.

There is a gem that aims to do just that: exifr

You can install it automatically with the following bundler line:

gem 'exifr'

EDIT:

I have personally switched to this fork of the same gem, which contains GPS helpers:

gem 'exifr', :git => 'git://github.com/picuous/exifr.git'

Use example:

EXIFR::JPEG.new('IMG_6841.JPG').gps?                # => true
EXIFR::JPEG.new('IMG_6841.JPG').gps                 # => [37.294112,-122.789422]
EXIFR::JPEG.new('IMG_6841.JPG').gps_lat             # => 37.294112
EXIFR::JPEG.new('IMG_6841.JPG').gps_lng             # =>-122.789422

edited Feb 17 '11 at 10:37

answered Feb 15 '11 at 15:51

Arnaud Leymet

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how would this work with remote assets that have been uploaded by Carrierwave and reside on S3? If you pass a full URL would it work? – amaseuk May 15 '12 at 16:35
@amaseuk I may be wrong, but I think that you only can use this with local files. But have a try and let us know – Arnaud Leymet May 16 '12 at 10:01
I would like to note that the "official" gem now has gps helpers also :) – Automatico Feb 24 '15 at 14:52

jaywards · Answer 2 · 2013-07-17T23:26:29.907

Just an update to the accepted answer above, which greatly helped me to get EXIFR working but has few issues:

To check if an image has GPS, I had to use EXIFR::JPEG.new('IMG_6841.JPG').exif?
To pull the latitude I used EXIFR::JPEG.new('IMG_6841.JPG').gps_latitude
And longitude is EXIFR::JPEG.new('IMG_6841.JPG').gps_longitude

Small issues but they had me spinning for a bit and might save someone time down the road.

Also, once I got my GPS coordinates from my photo I found this blog entry to help convert them from an array to Google Map friendly coordinates (i.e. 34.360826, -110.239368): http://www.cloudspace.com/blog/2009/02/16/decoding-gps-latitude-and-longitude-from-exif-in-ruby/

score 1 · Answer 3 · answered Feb 12 '11 at 14:47

you can't do it with paperclip. rmagick will help you neither. The only way I see is:

raw_props = %x[identify -format '%[exif:*]' #{path_to_image}].split("\n").collect{|a| a.split("=")}
properties = Hash[*raw_props.collect { |v| [v, v*2]}.flatten]

(pre: imagemagick installed and in the path, check with 'which identify')

score 0 · Answer 4 · answered Nov 13 '13 at 20:07

If you want use "higher level" solution (no exif directly), there is a gem https://github.com/aufi/photo_geoloader which loads latitude, longitude and altitude and can place it into rails model (in callback)

class Photo < ActiveRecord::Base
  before_create do
    PhotoGeoloader.new(photo.path).place_attributes self
  end
  ...

Getting GPS metadata from a picture with Paperclip

4 Answers4