Evaluation of Javascript Libraries
# for django integration.
Archive for the 'Javascript' Category
Sustainable transportation in Canada: An example of Exhibit map view
In Statistics Canada census, there was the result of employed labor mode of transportation for different areas in Canada. Although the data is quite straightforward, it would be nice to have a ‘map’ view for this data which will allow us easy to see the distinction geographically. It turns out that this is an interesting topic for Google map mashup.
By using Exhibit 2.0, a Javascript library which makes creating interactive easily, all we left to do is dumping the raw csv data with the latitude and longitude of each location into proper json format. With geopy, simplejson and Python build in module csv, here is an implementation:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 | import csv,re from geopy import geocoders import simplejson COLUMN = ["geocode","place_of_residence","total_Mode_of_transportation","car_truck_or_van_as_driver","car_truck_or_van_as_passenger","total_Sustainable_transportation","public_transit","walked","bicycle","other"] GMAPKEY="Google_Map_API_Key_here" def transformcsv2json(file,jsonfile='output.js'): reader = csv.reader(open(file)) column = COLUMN + ['city','province','latlng','label'] items=[] fc = 0 def getlatlng(place): # For some unknown reasons, sometimes gecoding fails several times before succeeds for i in range(25): try: g = geocoders.Google(GMAPKEY) place, (lat, lng) = g.geocode(place) latlng = str(lat) + ', ' + str(lng) return latlng except: print "|"*60,"Waring! ", place, " ", i, " times geocoding failed!" raise Exception for row in reader: city, province = mapLocationName(row[1]) if city and province: place = city + " " + province try: latlng = getlatlng(place) rowplus = row + [city, province, latlng, place] transItem = dict(zip(column,rowplus)) items.append(transItem) except: #We take a note of the place whcih fails in geocoding but still keeping on transforing next data row anyway. print "?"*60,"Error! ", place, " ", "geocoding failed!" fc += 1 print "#"*60, 'total number of geocoding fail: ', fc f = open(jsonfile,'w') f.write(simplejson.dumps({'items':items}, ensure_ascii=False)) f.close def mapLocationName(location): #Statistic Canada province abbreviation is different from google maps mapP = {'Alta.':'AB', 'B.C.':'BC', 'Man.':'MB','N.B.':'NB','N.L.':'NL','N.S.':'NS','N.W.T.':'NT','N.U.':'NU','Ont.':'ON','P.E.I.':'PE.','Que.':'QC','Sask.':'SK','Y.T.':'YT'} try: city, province = location.split(',') province = re.findall(r'\((.*)\)',province)[0] if re.search(r'\/',province): province = province.split('/')[0] province = mapP[province] except ValueError: city = location province = '' print 'Warning! ', location, ' parsing failed' return city,province if __name__ == '__main__': transformcsv2json('placeofresidence.csv','placeofresidence.js') |
Here is the result map mashup.
Serving static files in Django (in development mode)
I got stuck today while I was trying to have the javascripts running with Django.After reading Django document: How to serve static files , I finally figure out the step by step procedure:
step 1.
put this in urls.py
r'^site_media/(?P<path>.*)$', 'django.views.static.serve', {'document_root': '/path/to/media'}),
so now the file /path/to/media/js/myscript.js will be made available at the URL /site_media/js/myscript.js.
step 2.
In the template file, change the javascript directive line to <script src=”/site_media/js/myscript.js” type=”text/javascript”></script>
That’s it.However,there is a “big, fat disclaimer” in the document which said ”
Using this method is inefficient and insecure. Do not use this in a production setting. Use this only for development.
For information on serving static files in an Apache production environment, see the Django mod_python documentation.” … I think I need to spend some time on this topic in the future.