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Monday, July 06, 2009

Geocoding Large Data Sets...FREE

Hi all!

While I solidly believe GPS fieldwork is a great thing for a youth based project often I get questions about how can lat/long be created from an address or a spreadsheet. ESRI announced a week or so ago it’s free geocoder and it is great!(http://blogs.esri.com/Info/blogs/gisedcom/archive/2009/06/19/geocoding-using-arcgis-online.aspx)

However, one of the useful tools I would like to share today is the website Batch Geocode - http://www.batchgeocode.com/. It is very beneficial when you have LARGE data sets but equally as useful with a small dataset. You can very quickly copy information from a spreadsheet into this online tool and it will output the information with 2 new fields (bg_lat, bg_long –the bg stands for batchgeocode).

You can create a kmz file for use in Google Earth and you can also import this tabular data into ArcGIS, AEJEE and ArcExplorer with the x, y data!

A few tips that I will share from my experiences with this:

1) Try it out using their “data” that is preloaded before copying your own in. You will see how the process works with a small data set and what all of the fields/options are.

2) At the bottom of the process there is an option to “Save Map to a webpage” this is a webpage created on their website and you have no control over it other than to request it’s removal…which they are very nice to do if you mistakenly put up information that is sensitive (individuals names, phone numbers etc). I learned that the hard way.

3) As the geocoder is processing on the site. Watch your numbers of successfully geocoding data rows especially if you have a large dataset you have entered. The reason I suggest this is that if it slows down and appears to be stalling it is having a problem processing a specific address – if you write down the number that it seems to stall on you will know which row to go to in your spread sheet and look for potential addressing problems. I tried out a 300 person file and had 8 errors that I found this way. Also you can have it process in smaller sections by only copying in/out smaller sections of data at a time.

4) Always check the data once it loads in your GIS program or Google Earth – you may be able to quickly see errors in your information or in the processing. You can always rerun a single line of data. It is free so that doesn’t always mean correct!

I have shared this resource with professionals, youth groups and educators so if you have any questions please don’t hesitate to ask!

Shannon

Shannon H. White, PhD
Geospatial Extension Specialist
Department of Geography
University of Missouri
20 Stewart Hall
Columbia, MO 65211
Phone: (573) 884-0790
http://geospatial.missouri.edu

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