Get Started with GIS Mapping

1
Get Started with GIS Mapping

• Part 3 of 3
• Madhu Lakshmanan

2
Agenda

• Mapping your case data in aggregate form -
  Earthplot versus AFF Mapper
• Mapping your own data with AFF Mapper
• Recap
• To-Do
• Resources

3
Mapping your case data - aggregate

• Useful to denote differences in numbers at an
  aggregate level such as zip code or county level
  on top of other layers
• Need to have your data prepped as aggregates.
  Earthplot and AFF Mapper are some tools that
  create aggregate representations for GE.
  (GE-Graph is one other more complex tool.)
• Earthplot requires your aggregate data to be
  geocoded and can create graphs on top of GE. You
  dont need a base map to join your data to.
• AFF Mapper also requires your data to be
  aggregated but does not require geocoding. It
  creates the shaded graduated maps and not graphs.
  You need an appropriate shapefile (base map) to
  join your data to.

4
Earthplot

• Earthplot requires data such as the column that
  has been aggregated upon (e.g. zipcode), the
  actual aggregated values (e.g. counts), its
  latitude and longitude (the latitude and
  longitude of an area is usually created using its
  centroid) and any other data you might want to
  show in the description.

5
Earthplot

• In Earthplot, you will see 2 tabs, a Data tab and
  an Options Tab.
• Copy your Excel aggregate geocoded data and in
  Earthplot, in the Data tab, go to Edit-gtPaste and
  you will see your data appear in the same way
  that it appeared in Excel.

6
Earthplot

• Go to the Options tab and set various options. In
  this example, we use a Graduated sizes type of
  map with one variable.
• Set the columns to the correct items, i.e.
  longitude in column D, latitude in Column C etc.
  Make sure you have them right by looking at your
  data tab again. The variable column is the one in
  which the Count is stored.

7
Earthplot

• Select the shape to be circle for this example
  and Set the minimum and maximum sizes of your
  circle to be 0.05 and 0.3 to start with. You can
  keep tweaking these sizes and perhaps even the
  Ignore values box as you see your graph being
  created. Also set the color for your circles.

8
Earthplot

• Click on Plot to GE icon in the toolbar and you
  should see your circles appear on the map.
  Tweaking the sizes, colors, and perhaps setting a
  number in the ignore box will help create the
  graph you want.

9
Earthplot

• Once you have the graph you like, go to Earthplot
  and in the menu, choose Export to KML and give it
  a name and save. This way you will have a saved
  copy of your KML file.

10
AFF Mapper for your data

• In the earlier training we saw how AFF Mapper can
  be used to map census data onto base shapes, but
  we can also use it to map our own data as long as
  it is put in a form that the program understands.

11
AFF Mapper Data format

• Your data needs to be in aggregate form, in
  Excel, aggregated to the level that you want to
  categorize on. e.g. if you want to see
  county-wise color graduated map, then your data
  should be aggregated to the county level
• The columns that contain this level should be in
  both the base shapefile and your data file. e.g.
  your data file should contain the county
  code/name if that was your aggregation level.
• The top row of your Excel file can be the column
  headings. In the second row, you can have
  descriptive headings for your data. It is very
  IMPORTANT to use a colon in the 2nd row
  heading for those columns that are to be treated
  as NUMERIC, otherwise you will not be able to map
  those columns. E.g. you can call a column Case
  Totals

12
AFF Mapper Example

• An Excel file with Michigan County-wise data
  aggregates is chosen. The 2nd row headings are
  created making sure that the numeric data field/s
  have colons in the 2nd row headings.

First Row Headings
Second Row Headings
Note the colon
13
AFF Mapper Example

• A Michigan County level shapefile from the Census
  TIGER/Line was downloaded to serve as the base
  layer for the data.
• Start AFF Mapper and use the county map of
  Michigan as the Input shape.
• Then, under Select Join FileType, select XLS
  file and in the Join File box, browse for your
  previously created Excel file with the county
  aggregated data.

14
AFF Mapper Example

• Once that is loaded, set the Shape Join Field and
  the Table Join Field to be the same data, i.e.
  the level to which the data is aggregated, in
  this case County.
• The names of the columns might be different, but
  all that matters is that they contain the same
  type of data.
• In this example, we might set the Shape Join
  Field to CNTYDFP and the Table Join Field (which
  is our data) to CCODE.
• Alternatively, we could also use Name and CNAME
  but a code is usually more efficient than a name
  because of spellings etc.

15
AFF Mapper Example

• Hit Join tables and you should see the tables
  merge into one. Scroll to the right to see if
  your data is reflected in the table.

16
AFF Mapper Example

• Choose the County Name to be the Label Field and
  hit Render.
• You will be able to choose a classification
  scheme note that I have chosen Jenks Natural
  Breaks in this example.
• Then pick the variable to be mapped data,
  select the number of classes and colors and click
  OK

17
AFF Mapper Example

• Click on Output KML and enter a name for the
  output file. Then Click Go and wait for the
  Finished message.
• You can then open Google Earth and open this file
  and see the result.

18
AFF Mapper Example
19
Quick Recap
20
To-Do

• Assemble a set of tools for mapping
• Begin a library of base files and data files for
  mapping on your computer/server
• Find sources of data for your region many local
  governmental entities and health related
  organizations are good sources.
• Think about what sort of maps and visualizations
  work best for each purpose
• Discuss maps and mapping practices with peers.

21
LSNTAP GIS Resources

• Lunch and Map hour-long open house same time
  next week. Bring homework, questions, answers,
  food, ideas, resources (October 2nd, 2 pm
  Eastern)
• Roundtable Oct 8
• Next Training series 2 parts on December 4 and
  Dec 11.
• GIS mailing list resurrected do sign up and
  participate https//lists.mayfirst.org/cgi-bin/mai
  lman/listinfo/gis
• GIS Resources section on LSNTAP.org updated
• Set up a meeting with Madhu if you need support.
  Email madhu_at_lsntap.org
• Send links to any interesting mapping resources
  or data resources you find to madhu_at_lsntap.org