Issue in reading GPS info from JPG images ?
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Ahsan Abbas
on 29 Jan 2017
Commented: Walter Roberson
on 22 Mar 2020
I have some JPG images that are Geo-Tagged, am trying to read Lat & Long information from them in (Deg,Min,Sec) and want to convert them in decimal degree(DD), but getting some issue, My code is as follow
info = imfinfo('DSC_0011.JPG');
The result of above statement is as follow
**nfo.GPSInfo**
GPSVersionID: [2 3 0 0]
GPSLatitudeRef: 'N'
GPSLatitude: [33 34.2657 0]
GPSLongitudeRef: 'E'
GPSLongitude: [73 8.5707 0]
GPSAltitudeRef: 0
GPSAltitude: 456
GPSTimeStamp: [5 5 48.6400]
GPSSatellites: '05'
GPSMapDatum: 'WGS-84'
GPSDateStamp: '2016:03:31'
As you can see from above result in both rows Lat & Long seconds are 0, but in actually when i checked the properties of corresponding image it was this:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/160241/image.jpeg)
can some one help me to resolve the issue, i am facing same error while reading different images...
4 Comments
Image Analyst
on 2 Feb 2017
Yes but he may need more accurate than that. Even though there's a 4 meter accuracy in GPS, 1e-16 times the circumference of the earth is 4 nanometers. What if he needs to specify his location down to the nearest angstrom? ;-)
Walter Roberson
on 2 Feb 2017
Even if the position were represented in one double (instead of being split into degrees and minutes+fractions),
eps(40075)
ans =
7.27595761418343e-12
and angstrom is 10^10, so double is already capable of representing down to about 1/13th of an angstrom.
Accepted Answer
Image Analyst
on 29 Jan 2017
What did you use for the second method of getting GPS info? Why not just take the fractional part and multiply by 60 to get seconds:
secs = 0.2657 * 60; % = 15.942 seconds
It will give you the same number of seconds. What's wrong with doing that, if anything?
More Answers (2)
joévan ziebel
on 20 Mar 2020
Edited: joévan ziebel
on 20 Mar 2020
Hello,
I would like some help if it is possible for the function imfinfo().
I need a really good accuracy when I export my GPS coordinates from a jpg file.
More particularly on the longitude and on the latitude of the exif data.
Here is my code
filelist = dir('test/*.jpg');
nfiles = length(filelist);
fid = fopen('localisation.csv','w');
Entete={'file','latitude','longitude'};
fprintf(fid,'%s,%s,%s\n',Entete{:});
for i=1:nfiles
disp(['Traitement du fichier n° ',sprintf('%d',i)])
probname = filelist(i).name;
filesource = strcat('test/',probname);
f = imfinfo(filesource);
latitudeTab=f.GPSInfo.GPSLatitude;
longitudeTab=f.GPSInfo.GPSLongitude;
latitude = dms2degrees(latitudeTab);
longitude = dms2degrees(longitudeTab);
formatSpec = '%s,%f,%f\n';
str = sprintf(formatSpec,probname,latitude,longitude);
fprintf(fid,str);
end
fclose(fid);
Don't pay attention to the entire code. The problem is only when I save the data in the f variable.
Matlab rounds the value of latitude and longitude and I don't know how to solve this. Maybe it's the imfinfo function that does this and I cannot do anything about ?
Here is the real value in the jpg file :
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/278316/image.jpeg)
Here is the rounded value with matlab :
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/278317/image.jpeg)
I already tried with the vpa and with a new Digits, but it seems it doesn't change something. I need the exact value, not a rounded one.
Thanks for your help in advance !
3 Comments
Walter Roberson
on 22 Mar 2020
Besides that: the difficulty is probably in your choice of default format for displaying values. Try using
format long g
and also go into Preferences and adjust the default display format.
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