Taking the Grunt out of Geotags

Here's a matlab script to automatically compile all geo-tagged images from a directory and all its subdirectories into a Google Earth kml file showing positions and thumbnails

	close all;clear all;clc
	addpath('/path/where/googleearth/toolbox/is')
	% get main directory (Projects directory)
	pathFolder=uigetdir();
	% get list of subfolders
	d = dir(pathFolder);
	isub = [d(:).isdir];
	nameFolds = {d(isub).name}';
	nameFolds(ismember(nameFolds,{'.','..'})) = [];
	% prompt user to select which subfolders to process
	[s,v] = listdlg('PromptString','Select folders:',...
	'SelectionMode','multiple',...
	'ListString',nameFolds);
	% use only those directories
	directories=char(nameFolds(s));
	for md=1:size(directories,1)
	% get list of subfolders
	d = dir(strtrim([pathFolder,filesep,directories(md,:)]));
	isub = [d(:).isdir];
	nameFolds = {d(isub).name}';
	nameFolds(ismember(nameFolds,{'.','..'})) = [];
	subdirectories{md}=char(nameFolds);
	end
	mattime=[]; timestring=[]; lat=[]; lon=[]; filenames={};
	direc=[];
	counter=0;
	for dd=1:size(directories,1)
	for sd=1:size(subdirectories{dd},1)
	if isempty(strmatch(strtrim(subdirectories{dd}(sd,:)),'dng')) &&...
	isempty(strmatch(strtrim(subdirectories{dd}(sd,:)),'crw'))
	files1=ReadImDir(strtrim([pathFolder,filesep,strtrim(directories(dd,:)),...
	filesep,strtrim(subdirectories{dd}(sd,:))]),'JPG');
	files2=ReadImDir(strtrim([pathFolder,filesep,strtrim(directories(dd,:)),...
	filesep,strtrim(subdirectories{dd}(sd,:))]),'jpg');
	files=char(files1,files2); %,files3
	for k=1:size(files,1)
	in=strtrim([pathFolder,filesep,strtrim(directories(dd,:)),filesep,strtrim(subdirectories{dd}(sd,:)),...
	filesep,strtrim(files(k,:))]);
	if isempty(regexp(in,'ppm.jpg', 'once'))
	counter=counter+1;
	filenames{counter}=in;
	[stat,res]=system(['exiftool -h "',in,'"']);
	latstr=res(regexp(res,'>GPS Latitude<')+22:regexp(res,'>GPS Latitude<')+41);
	if ~isempty(latstr)
	deg=str2double(strtrim(latstr(1:2)));
	mins=str2double(strtrim(latstr(8:9)));
	secs=str2double(strtrim(latstr(16:end)));
	lat=[lat; deg+ mins/60 + secs/3600];
	lonstr=res(regexp(res,'>GPS Longitude<')+22:regexp(res,'>GPS Longitude<')+42);
	deg=str2double(strtrim(lonstr(2:4)));
	mins=str2double(strtrim(lonstr(10:11)));
	secs=str2double(strtrim(lonstr(17:end)));
	lon=[lon; deg+ mins/60 + secs/3600];
	timestr=res(regexp(res,'>GPS Date/Time<')+23:regexp(res,'>GPS Date/Time<')+41);
	y=str2double(timestr(1:4)); m=str2double(timestr(6:7)); d=str2double(timestr(9:10));
	H=str2double(timestr(12:13)); M=str2double(timestr(15:16)); S=str2double(timestr(18:19));
	if S==0
	S=S+1;
	end
	mattime=[mattime;datenum([y,m,d,H,M,S])];
	timestring=[timestring;datestr(datenum([y,m,d,H,M,S]))];
	direc=[direc;dd];
	else
	lat=[lat;NaN]; lon=[lon;NaN];
	timestr=res(regexp(res,'>Create Date<')+21:regexp(res,'>Create Date<')+39);
	y=str2double(timestr(1:4)); m=str2double(timestr(6:7)); d=str2double(timestr(9:10));
	H=str2double(timestr(12:13)); M=str2double(timestr(15:16)); S=str2double(timestr(18:19));
	if y==2012
	y=y+1;
	end
	if S==0
	S=S+1;
	end
	mattime=[mattime;datenum([y,m,d,H,M,S])];
	timestring=[timestring;datestr(datenum([y,m,d,H,M,S]))];
	direc=[direc;dd];
	end
	end % if not ppm.jpg
	end %k
	end % if not dng or crw
	end %sd
	end %dd
	thumbfiles=cell(size(filenames));
	for i=1:length(lat)
	thumbfiles{i}=[filenames{i},'_thumb.jpg'];
	end
	kmlStr=cell(1,length(lat));
	for i=1:length(lat)
	system(['exiftool -b -ThumbnailImage ',filenames{i},' > ',thumbfiles{i}])
	kmlStr{i} = ge_point_new(-lon(i),lat(i),0,...
	'description',['<a href="',filenames{i},'">link to file</a>'] ,...
	'iconURL',thumbfiles{i},...
	'name',filenames{i}(regexp(filenames{i},'IMG'):end));
	end
	tmp=[];
	for i=1:length(lat)
	tmp=[tmp,eval(['kmlStr{',num2str(i),'}'])];
	end
	ge_output('points.kml',...
	ge_folder('points',tmp));
	system(['google-earth "',pwd,filesep,'points.kml" &'])
	save('photo_res','mattime','lat','lon','direc','timestring','filenames','directories')

view raw geophotos2kml.m hosted with ❤ by GitHub

Like most of my matlab scripts, it's essentially just a wrapper for a system command. It requires exiftool for the thumbnail creation (available on both *nix and for Windows). It also needs the (free) Google Earth toolbox for Matlab.

Right now it's just set up for JPG/jpg files, but could easily be modified or extended. As well as the kml file (Google Earth will launch as soon as the script is finished) it will save a matlab format file contining the lats, longs, times and filenames.

Outputs look a little like this (a selection of over 30,000 photos taken in Grand Canyon)

A cooler shell prompt

In ~/.bashrc:

export PS1='\[\033[1;34m\]\t\[\033[0m\] \[\033[1;35m\]\u\[\033[0m\]:\[\033[1;35m\]\W\[\033[0m\] \[\033[1;92m\]$(__git_ps1 "(%s)")\[\033[0m\]$ '

view raw prompt.sh hosted with ❤ by GitHub

time: username: directory

much better!

How to start a BASH script

Use chance!

	# flip a coin
	FLIP=$(($(($RANDOM%10))%2))
	# if heads, use cowsay to present your splash
	if [ $FLIP -eq 1 ]
	then
	# start with some wisdom
	fortune -s | cowsay -n | zenity --text-info --title="Your message here" --width 500 --height 500
	else
	# or start with some other msg
	figlet DAN ROCKS | zenity --text-info --title="Your message here" --width 600 --height 200
	fi

view raw cow flip.sh hosted with ❤ by GitHub

Flip a coin. If heads, allow fortune to generate a quotation and cowsay to present it:

If tails, figlet your 'splash' message:

Discuss

Destination point given distance and bearing from start point

You have starting points:

xcoordinate, a list of x-coordinates (longitudes)

ycoordinate, a list of y-coordinates (latitudes)

num_samples, the number of samples in the plane towards the destination point

bearings:

heading, a list of headings (degrees)

and distances:

range, a list of distances in two directions (metres)

This is how you find the coordinates (x, y) along the plane defining a starting point and two end points, in MATLAB.

	R = 6371 % mean radius of the Earth, in km
	% pre-allocate for results
	x=cell(1,num_points)
	y=cell(1,num_points)
	for k=1:num_points
	% COORDINATES OF STARTING POINT
	lon1=xcoordinate(k) ;
	lat1=ycoordinate(k) ;
	d=range(k)/1000; %range in km
	b1=heading(k); % bearing in degrees
	% FIND FINAL BEARING FROM INITIAL BEARING
	if b1=>180
	b2 = b1-180;
	else
	b2 = b1 + 180;
	end
	% CONVERT TO RADIANS
	b1= b1.*(pi/180);
	b2= b2.*(pi/180);
	dOverR=d/R; % angular radians
	% LATITUDE, END POINT 1
	lat2 = asin( sin(lat1*(pi/180))*cos(dOverR) + ...
	cos(lat1*(pi/180))*sin(dOverR)*cos(b1) ) / (pi/180);
	% LONGITUDE, END POINT 1
	lon2 = lon1 + atan2( sin(b1)*sin(dOverR)*cos(lat1), ...
	cos(dOverR)-sin(lat1)*sin(lat2) ) ;
	% LATITUDE, END POINT 2
	lat3 = asin( sin(lat1*(pi/180))*cos(dOverR) + ...
	cos(lat1*(pi/180))*sin(dOverR)*cos(b2) ) / (pi/180);
	% LONGITUDE, END POINT 2
	lon3 = lon1 + atan2( sin(b2)*sin(dOverR)*cos(lat1), ...
	cos(dOverR)-sin(lat1)*sin(lat2) ) ;
	% FIND COORDINATES IN THAT PLANE
	y{k}=linspace( min([lat2,lat3]),max([lat2,lat3]), num_samples(k));
	x{k}=linspace( min([lon2,lon3]),max([lon2,lon3]), num_samples(k));
	end

view raw EndPoint_bearing_Distance.m hosted with ❤ by GitHub

Routine BASH memory aid

Some common things I do in BASH

	#Do something if a file exists
	if [ -f $target_dir"/$target_file" ]
	then do something here
	fi
	#Calculate pi using bc
	pi=`echo "4*a(1)" | bc -l`
	#Convert degs to radians
	rad=`echo "$deg*($pi/180)" | bc -l`
	#Calculate tangent in degrees
	tandeg=$(echo "s($rad)/c($rad)" | bc -l)
	#List subdirectories in pwd
	subdir=$(ls -d */)
	#Clear screen
	printf "\033c"
	#Calling python to do a math operation rather than bc , e.g. a ceil:
	round_up=$(python -c "from math import ceil; print ceil($variable)")
	#Pass arguments to script from command line
	args=("$@")
	first_arg=${args[0]}
	second_arg=${args[1]}
	#Pass number lines in file to variable
	numrecords=$(wc -l $target_dir"/file.ext" | awk -F" " '{print $1}')
	#Delete every file which is not a *.ext file
	find $target_dir -maxdepth 1 -type f ! -iname "*.ext" | xargs -I '{}' rm '{}'
	#Pipe the first two columns of file to new file
	awk '{print $1 " " $2 " " (-$3) }' $xyzfile".dat" > $xyzfile"new.dat"
	#Max and min of a column (n) in file
	n=2
	lims=$(awk 'BEGIN{ max = -999999999 ; min = 9999999999 } $n > max {max = $n} $n < min {min = $n} END{ print min, max }' $file)
	#Find a replace in file (NaNs with Os)
	sed -i 's/NaN/0/g' file.ext
	#Select a directory using zenity and pass to variable
	export my_dir=`zenity --file-selection --title="Select a Directory" --directory`

view raw bash memory aid.sh hosted with ❤ by GitHub