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greglandrum/scrape.height.py

Created February 28, 2013 06:25
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scrape.height.py
import simplejson,urllib,random
idx = random.randint(1,10000000)
import sys,re,os,datetime
CHART_BASE_URL = 'http://chart.apis.google.com/chart'
ELEVATION_BASE_URL = 'http://maps.google.com/maps/api/elevation/json'
tInterval=1800
pltWidth=400
pltHeight=200
if len(sys.argv)==3 and sys.argv[2]!='-' and os.path.splitext(sys.argv[2])[-1]!='.gpx':
outF = file(sys.argv[2],'w+')
inNames = [sys.argv[1]]
else:
outF = sys.stderr
inNames = sys.argv[1:]
from xml.etree import cElementTree as ET
data=[]
for inF in inNames:
line=[]
times=[]
inF = file(inF,'ru')
et = ET.ElementTree(file=inF)
vers='.//{http://www.topografix.com/GPX/1/1}'
pts = et.findall(vers+'trkpt')
if not pts:
vers='.//{http://www.topografix.com/GPX/1/0}'
pts = et.findall(vers+'trkpt')
if not pts:
vers='.//{http://www.topografix.com/GPX/1/0}'
pts = et.findall(vers+'rtept')
if not pts:
raise ValueError,'could not find any points'
#for pt in pts:
# line.append((float(pt.get('lat')),float(pt.get('lon'))))
for pt in pts:
line.append('%s,%s'%(pt.get('lat'),pt.get('lon')))
tme=pt.find(vers+'time')
t = tme.text
times.append(datetime.datetime.strptime(t,'%Y-%m-%dT%H:%M:%SZ'))
data.append((line,times))
from math import *
def geodist(p1,p2):
"""
formula from here:
http://www.movable-type.co.uk/scripts/latlong.html
"""
p1 = [float(x) for x in p1.split(',')]
lat1,lon1=p1
p2 = [float(x) for x in p2.split(',')]
lat2,lon2=p2
R = 6371
dLat = pi*(lat2-lat1)/180.
dLon = pi*(lon2-lon1)/180.
lat1 = pi*lat1/180.
lat2 = pi*lat2/180.
a = sin(dLat/2) * sin(dLat/2) + \
sin(dLon/2) * sin(dLon/2) * cos(lat1) * cos(lat2)
c = 2 * atan2(sqrt(a), sqrt(1-a));
d = R * c
return d
html="""<html>
<head>
<script type="text/javascript" src="http://www.google.com/jsapi"></script>
<script type="text/javascript">
google.load('visualization', '1',{'packages':['corechart']});
google.setOnLoadCallback(drawVisualizations);
function drawVisualizations() {
var divs = document.getElementsByTagName('div');
for(var i=0;i<divs.length;i++){
var div = divs[i];
if( div.className.search('gpsplt')!=-1){
var idx = div.className.split('_')[1];
var dtbl = eval('dtbl_'+idx);
drawVisualization(dtbl);
}
}
}
function drawVisualization(dT) {
chart=new google.visualization.ComboChart(document.getElementById('vis_div'));
options={seriesType:'line',
series:{2:{type:'scatter'},3:{type:'scatter'}},
vAxis:{title:'Height'},
hAxis:{title:'Distance'},
legend:{position:'none'}
};
chart.draw(dT,options);
}
</script>
</head>
<body style="font-family: Arial;border: 0 none;">
<script type="text/javascript">
var dtbl_%(idx)d;
dtbl_%(idx)d = new google.visualization.DataTable();
dtbl_%(idx)d.addColumn('number','Distance');
dtbl_%(idx)d.addColumn('number','Height');
dtbl_%(idx)d.addColumn('number','HeightInterval');
dtbl_%(idx)d.addColumn('number','Interval');
dtbl_%(idx)d.addRows([
%(dRows)s
]);
</script>
<div id="vis_div" class="gpsplt_%(idx)d" style="width: %(pltWidth)dpx; height: %(pltHeight)dpx;"></div>
</body>
</html>
"""
clip="""
<script type="text/javascript">
var dtbl_%(idx)d;
dtbl_%(idx)d = new google.visualization.DataTable();
dtbl_%(idx)d.addColumn('number','Distance');
dtbl_%(idx)d.addColumn('number','Height');
dtbl_%(idx)d.addColumn('number','HeightInterval');
dtbl_%(idx)d.addColumn('number','Interval');
dtbl_%(idx)d.addRows([
%(dRows)s
]);
</script>
<div id="vis_div" class="gpsplt_%(idx)d" style="width: %(pltWidth)dpx; height: %(pltHeight)dpx;"></div>
"""
dRows=[]
dists=None
minElev=100000
for i,(line,times) in enumerate(data):
pieces = []
for j in range(0,len(line),50):
args = {'sensor':'false',
'locations':'|'.join(line[j:min(j+50,len(line))])}
url = ELEVATION_BASE_URL + '?' + urllib.urlencode(args)
rawd=urllib.urlopen(url).read()
pieces.append(simplejson.loads(rawd))
pts = []
for piece in pieces:
pts.extend(piece['results'])
stime=times[0]
shiftimes=[(x-stime).seconds for x in times]
if dists is None:
dists=[0]
else:
dists=[dists[-1]]
for j in range(1,len(line)):
d = dists[j-1]+geodist(line[j-1],line[j])
dists.append(d)
assert len(dists)==len(shiftimes)
intervals=[]
for j in range(1,len(shiftimes)):
t1 = shiftimes[j-1]
t2 = shiftimes[j]
if (t2//tInterval)>(t1//tInterval):
intervals.append(j)
elevs=[x['elevation'] for x in pts]
minElev = min(minElev,min(elevs))
sis1=['null']*len(times)
sis2=['null']*len(times)
for interval in intervals:
sis1[interval]='%.1f'%elevs[interval]
sis2[interval]='%.1f'%minElev
sis2[0]=str(minElev)
rowD = zip(dists,elevs,sis1,sis2)
dRows.append(','.join(["[%.2f,%.1f,%s,%s]"%(x,y,z,a) for x,y,z,a in rowD]))
dRows = ','.join(dRows)
print clip%locals()
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