Topojson install

1. Install Anaconda to get your python 2.7.
2. Install .Net Framework - dotNetFx45_Full_setup.exe
3. Uninstall the Microsoft Visual C++ 2010 instances.
4. Install the Microsoft SDK - winsdk_web.exe  #http://www.microsoft.com/en-us/download/details.aspx?id=8279
5. Install Node.js - http://nodejs.org/download/
6. Open your command prompt as an administrator 
  >Start
  >"cmd" in Search for All Programs
  >Ctrl-RightClick on CMD and "Run as Administrator"
7. Set your environment for the SDK (this was tricky to figure out!)
  > call "C:\Program Files\Microsoft SDKs\Windows\v7.1\bin\Setenv.cmd" /Release /x64
  (if it doesn't work try "/x86" instead of "/x64" in the above #use /x86 for Windows xp
8. Install your Topojson from NPN
  >npm install -g topojson

> topojson --id-property BASIN -p name -o Basins_topo.json Basins.geojson <
 1. --id-property - <The unique ID field?>
  2. -p name - <list fields to bring over.  "" will return all fields>
  3. -o - <the name of your output file - I use *_topo.json to differentiate from *.json and *.geojson>
  4. Finally the input file.)
  
  
  
topojson has file size limit.   
How large are those input GeoJSON files? If they are anything near ~1GB,
you must use shapefile input rather than GeoJSON, since shapefiles are more
compact and can be streamed. (Node.js has a maximum buffer size of 1GB, which makes 
it difficult to parse JSON files larger than that.) You can also increase the amount
of memory available using node --max-old-space-size=XXXX bin/topojson, 
where XXXX is a large number of megabytes. –  mbostock May 3 '13 at 4:55