Get Started with GIS Mapping

1. Get Started with GIS Mapping Part 2 of 3 Madhu Lakshmanan

2. Agenda • Google Earth – best practices • Data Preparation – geocode, aggregate, planning, data formatting ... • Mapping your case data • As point data • As aggregates • AFF Mapper – as prescribed  • Resources and downloads • Homework

3. Google Earth – some best practices • Play, Practice, Patience • Save as and keep your KML files organized in a separate folder on your drive. • Clear cache regularly unless unsaved data • Save without too many standard layers to keep kmz size down for emailing etc. • Use transparency slider • Actual screenshots better than using the inbuilt GE copy tool – only copies the GE map and not any of your custom overlays • Look at KML in free time – very much like XML.

4. Data Preparation - Planning • Having some idea of what you want to achieve with your map • What data do you have already? • What data do you need to acquire? • If you have to convert your data, what conversion tools do you need? • What maps can you reuse? • Data origin, metadata, processing • Discuss with other users, colleagues, peers

5. Data Preparation - Geocoding • Can geocode at different address levels like state, county, zipcode, complete address, etc. • Multiple ways, differences in accuracy, daily limits, one time activity • Using BatchGeocoder.com • Using KMLGeocoder on desktop • Zip data with lat/long for each state

6. Data Preparation - Aggregate • Useful to graph case address data at a higher level like zipcode/county • Using Excel to do sorting/subtotals • Using the aggregate geocoded data in tools like Earthplot • Certain tools need your data to be either in number format or don’t care. Knowing which can help in troubleshooting Data Preparation - Formatting

7. Mapping your case data - points • Directly enter addresses into GE one by one. (can import bulk if using Pro version) • Use a tool like KMLGeocode to take your Excel address data and convert to KML directly – no identifying info needed other than address data. Limit is 5000 a day. • GE shows a map with a scatter plot of your case data. A screenshot of this will not reveal any specific address information to a viewer but sharing kml will do that.

8. Mapping your case data - aggregate • Useful to denote differences in numbers at an aggregate level such as zip code on top of other layers • Earthplot is a simple tool that creates such graphs for GE. (GE-Graph is one other more complex tool.) • Need to have your data prepped as aggregates and geocoded beforehand.

9. AFF Mapper – Basic • Created to make maps using census boundary files and American Fact Finder data • Rule-based, but simple to follow • Find a shapefile from http://www2.census.gov/cgi-bin/shapefiles/national-filesThis is a one time task for a particular geography, so make sure to extract, rename and save the file safely. • Extract to a folder on your computer that you can find. There will be multiple files in the folder.

10. AFF Mapper – Basic • Go to the American Fact Finder website for datasets. http://factfinder.census.gov/home/saff/main.html?_lang=en • In the left panel, choose Data Sets and a survey/census • Choose the option to create a custom table • Select a geographic type and subtypes if applicable. • Follow the prompts to select a table from the list • Filter by data elements (these will be the columns in your final excel file) • Sometimes you can further filter the results to restrict the number of rows • View the table before downloading. • In the toolbar above the table, you have an option to print/download. Choose download, choose to save as an Excel file with the descriptive field names and save. Extract the zip file to a well named folder.

11. AFF Mapper – Basic • Start up the AFF Mapper • Click on Input file and choose your shapefile that you had downloaded from the TIGER site earlier. • Once that loads up, select XLS from the Join File Type and click on Join Table. Browse to your Factfinder downloaded xls file and select it. • It usually detects the common fields from the two files, but you might just want to see that it has done it right. • Then click Join Tables. You should see the two tables merge together. • Select the field that you want to be a label on your map • Click Render. Another box opens and you can choose your field to be mapped and set the mapping options (good choice for numeric data is the Jenks breaks method). Set colors etc and say ok. • You return to the original screen, where you specify your output filename and click Go. This will create a KML file for you. You can then open it in GE.

12. Resources and Interesting Mapping Applications - 2 • Download applications here http://lsntap.org/GIS_Resources_for_Google_Earth • KMLGeocoder • EarthPlot • AFFMapper • Shp2KML • KML2CSV converter • Statewise Geocoded Zip codes + Excel tool • Regional Legal Aid boundary files

13. Homework • Create a map using some sample data using Earthplot. • Create 2 maps using the AFF mapper and data from the American Fact Finder datasets.