Get location information quickly

I usually develop with Rails. At that time, I was addicted to an unexpected part in acquiring location information, so is it a memorandum of the created code? Heads up? I will leave it as. If you want to see only the situation where GPS information cannot be obtained, skip to GPS could not be obtained.

Immediately, I will try to confirm the location information in the terminal. You can also copy and paste the code.

environment: Ruby2.6.6 ImageMagick 7.0.10-34

Create a Ruby file

This time I created a main.rb file in a directory called gps_test. Then write the following code.

main.rb

require 'rmagick'

img = Magick::ImageList.new(File.expand_path('~/Downloads/Image data name'))
p img
p img.get_exif_by_entry('GPSLatitude')

#Latitude: Convert to decimal number and output
exif_lat = img.get_exif_by_entry('GPSLatitude')[0][1].split(',').map(&:strip)
latitude = (Rational(exif_lat[0]) + Rational(exif_lat[1])/60 + Rational(exif_lat[2])/3600).to_f
p latitude

#Longitude: Convert to decimal number and output
exif_lng = img.get_exif_by_entry('GPSLongitude')[0][1].split(',').map(&:strip)
longitude = (Rational(exif_lng[0]) + Rational(exif_lng[1])/60 + Rational(exif_lng[2])/3600).to_f
p longitude

Enter the image file you want to read (IMG_8765.jpg, etc.) in the image data name.

If you do Magick :: ImageList.new (File.expand_path ('~ / Desktop / image data name')), it will be read from Desktop. (As you see it ..)

In my case, the read permission of the download directory was not set, so I loaded it as Desktop.

Install RMagick

Execute the following from the terminal in the project

$ gem install rmagick

At this time, if an error occurs, this will be helpful. Installation failed with gem install rmagick Cannot install with bundle install "rmagick"

Run a Ruby program

$ ruby main.rb

Execution result

ruby main.rb
[/Users/tn/Desktop/Akihabara.jpeg JPEG 1200x1600 1200x1600+0+0 DirectClass 8-bit 535kb]
scene=0
[["GPSLatitude", "35/1, 41/1, 5920/100"]]
35.699777777777776
139.7717

Now you have the latitude and longitude of GPS!

GPS could not be obtained

To conclude, ** I couldn't get GPS because it was an HDR image when I took it with my iPhone. ** That means.

There is a function called "Auto HDR" in the iPhone settings.

Automatic HDR: A function that allows multiple photos to be taken continuously at high speed with various exposures and combined with a photo that clearly expresses bright areas and shadow details.

If you have an iPhone terminal, you can see the map by setting it with location information = GPS will also be acquired I thought, but I couldn't get it with the contents described at the beginning. (If you know how to get it, please let me know ...)

The program shouldn't be wrong, so why can't I get it .. You may want to make sure that automatic HDR is turned off. I wonder how many hours I wasted with this .. crying Turn off iPhone automatic HDR

I was doing a simple check from the preview to see if the location information was included. [Mac] How to quickly check the location information (geotag) of an image

** However, why can't GPS be read even though the location information is set? I tried to verify if there is a setting pattern. ** **

Pattern verification (location information setting is ON)

Pattern 1 both ON Turn on "automatic HDR (synthesis function)" Result: Turn on "Leave normal photo" → GPS cannot be read

Pattern 2 one side Turn on "automatic HDR (synthesis function)" Result: "Leave a normal photo" is turned off → GPS cannot be read

Pattern 3 one side "Automatic HDR (synthesis function)" is turned off. Result: "Leave a normal photo" is turned off → GPS cannot be read

Pattern 4 State of reference image "Automatic HDR (synthesis function)" is turned off. Result: Turn on "Leave normal photo" ** → GPS can be acquired **

reference image:

Summary

It's self-taught and inefficient, but this is another experience! !! I think I have grown a little this time as well, and I will continue to take on the challenge of development. It was a basic content, but I hope you can refer to the acquisition method and precautions.

reference

Use R Magick to convert image Exif location information to decimal value