Get Started with GIS Mapping

Part 2 of 3

Madhu Lakshmanan

AgendaGoogle Earth – best practicesData Preparation – geocode,

aggregate, planning, data formatting ...

Mapping your case data◦As point data ◦As aggregates

AFF Mapper – as prescribed Resources and downloadsHomework

Google Earth – some best practicesPlay, Practice, PatienceSave as and keep your KML files organized

in a separate folder on your drive. Clear cache regularly unless unsaved dataSave without too many standard layers to

keep kmz size down for emailing etc.Use transparency sliderActual 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.

Data Preparation - PlanningHaving some idea of what you want to

achieve with your mapWhat 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, processingDiscuss with other users, colleagues,

peers

Data Preparation - GeocodingCan 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 desktopZip data with lat/long for each state

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 - Aggregate

Data Preparation - Formatting

Mapping your case data - pointsDirectly 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.

Mapping your case data - aggregateUseful 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.

AFF Mapper – BasicCreated to make maps using census

boundary files and American Fact Finder data

Rule-based, but simple to followFind a shapefile from

http://www2.census.gov/cgi-bin/shapefiles/national-files This 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.

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.

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.

Resources and Interesting Mapping Applications - 2Download applications herehttp://lsntap.org/GIS_Resources_for_Google_Earth

◦KMLGeocoder◦EarthPlot◦AFFMapper◦Shp2KML◦KML2CSV converter◦Statewise Geocoded Zip codes + Excel

tool◦Regional Legal Aid boundary files

Homework

1. Create a map using some sample data using Earthplot.

2. Create 2 maps using the AFF mapper and data from the American Fact Finder datasets.