upsample_and_shweta.m

load('gps_feature_and.mat')
gap = 1*60*1000 % upsample rate: 1 per minute 
epochtime = 1443672000000;  % 2015/10/01  12:00 am, used to calculate hour of the day quickly
survey_interval = 14; % cahnge to 14 for phq9
coverpercent_threshod = 0.4;  % how many percentage of one survey period needs to be covered 
for i = 1:size(gpsData,2)
    i
    new=[];
    temp = gpsData{1,i};
    if length(temp)==0
        continue;
    end
    temp(:,5)=0;
    temp =sortrows(temp,4);
    
    startt=temp(1,4);
    endt=temp(end,4);
    len = size(temp,1);
    j=1;
    c=0;
    startt = startt+gap;
    for z=[1:100000]
        if j+1>len;
            break;
        end
        if temp(j,11)==-3 % no upsampling for activity data
            j = j+1;
            continue;
        end
        if temp(j,4)<startt
            t = [0 0 0 mod(((temp(j,4)-epochtime)/3600000),24)];
            % time dependent
            if t(1,4)>=6 & t(1,4)<22
                if( temp(j,9)== 7 | 6 )
                    th=2;
                else
                    th=1;
                end
            else
                th=1;
            end
             
%             if temp(j,11) ==-1 % GPS up to 15 minutes 
                th=1/4;
%             end
            if t(1,4)>=0 & t(1,4)<6
                ttmp = ((temp(j,4)-epochtime)/3600000);
                decvalue = ttmp - floor(ttmp/24)*24;
                th = min(6,6-decvalue);
            end
            n=th*3600000/gap;
            tmp=temp(j,:);
            c=0;
            j=j+1;
        else
            new(end+1,:)=[tmp(1,1:3) startt tmp(1,5:end)];
            c=c+1;
            startt = startt+gap;
            if c>n
                startt = temp(j,4);
                startt = startt+gap;
            end
        end
    end
    gpsData{1,i} = new;
end
%calculate the moving spped
th=1;
c=0
for k = 1:length(gpsData)
    tmp = gpsData{1,k};
    len = length(tmp);
    for l = 2:len
        fP1Lat = tmp(l-1,2);
        fP1Lon = tmp(l-1,3);
        fP2Lat = tmp(l,2);
        fP2Lon = tmp(l,3);
        fRadLon1 = (pi/180).*(fP1Lon);
        fRadLon2 = (pi/180).*(fP2Lon);
        fRadLat1 = (pi/180).*(fP1Lat);
        fRadLat2 = (pi/180).*(fP2Lat);
        fD1 = abs(fRadLat1 - fRadLat2);
        fD2 = abs(fRadLon1 - fRadLon2);
        fP = power (sin(fD1/2), 2) + cos(fRadLat1) * cos(fRadLat2) * power (sin(fD2/2), 2);
        d = 6371.137 * 2 * asin(sqrt(fP)) ;
        t = (tmp(l,4)-tmp(l-1,4))/1000;
        if (d*3600/t >th)
            gpsData{1,k}(l,5)=1;
            c=c+1;
            gpsData{1,k}(l-1,5)=1;
        end
    end
end

id = cellfun('length',gpsData);
gpsData(id==0)=[];

for k = 1:length(gpsData)
    remove = [];
    tmp = gpsData{1,k};
    len = length(tmp);
    for l = 2:len
        if(tmp(l,4)-tmp(l-1,4)==0)
            remove=[remove;l];
        end
    end
   tmp(remove,:) = []; 
   gpsData{1,k} = tmp;
end

sdc=[]
for i = 1:size(gpsData,2)
    temp = gpsData{1,i};
    if length(temp)==0
        continue;
    end
    dc =1;
    for di=2:length(temp)
        if temp(di,9)~=temp(di-1,9)
            dc=dc+1;
        end
    end
    sdc = [sdc;dc];
end

%calculate the time coverage
relen = [];
for i =1:length(gpsData)
    tmp = gpsData{1,i};
    relen=[relen length(tmp)];
end
save('gps_feature_and_up_shweta.mat','gpsData');