Geocoding: From Excel to TileMill (Part II)

This continues from the previous post, where the iPhone GPS data has been batch exported to Excel BUT in a weird DMS format rather than the DD format that we need in order to import into TileMill. Unfortunately, there is no magic button or plugin for this, but in the end… it turns out… its not that hard after all. Doh.

D + M/60 + S/3600 = DDIn Excel:
=SUM([@[D-Lat]]+[@[M-Lat]]/60+[@[S-Lat]]/3600)
=SUM([@[D-Lon]]+[@[M-Lon]]/60+[@[S-Lon]]/3600)

Note that iPhone’s format may actually be D,M(in decimals) without an S value.

Screen Shot 2012-11-08 at 10.36.40 AM.png

Degree:Minutes:Seconds GPS values converted to Decimal Degrees!
(See Lat and Lon column. TileMill will understand any of the following column headers: latitude, longitude, lat, long,lon, x, y.)

Data successfully imported into TileMill Layer!

Plotted successfully! But what is this? IT IS ALL EMPTY!?????

Oh so I forgot to add in any shape layers. So next we need an ESRI Shapefile for city of Paris available here here and here from metro.teczno.com and downloads.cloudmade.com respectively, based on OpenStreetMap data. [See also: Adding Layers in TileMill]