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Get Started with GIS Mapping
Part 3 of 3
Madhu Lakshmanan
Agenda

Week 2 – Redux
◦ Earthplot
AFF Mapper – using your own data
 Recap
 To-Do
 Resources

Mapping your case data - aggregate
Useful to denote differences in numbers at an
aggregate level such as zip code on top of other
layers
 Need to have your data prepped as aggregates
and geocoded beforehand.
 Earthplot is a simple tool that creates such
graphs for GE. (GE-Graph is one other more
complex tool.)
 AFF Mapper also requires your data to be
aggregated but does not require geocoding. It
creates the shaded graduated maps and not
graphs

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.
Zip
Cases
Latitude
Longitude
87002
1
34.5756
-106.588
87004
4
35.4078
-106.82
87005
1
35.1385
-108.242
87006
1
34.4828
-106.805
87016
1
34.748
-106.158
87017
3
36.2277
-106.819
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->Paste and you will see your data appear in the
same way that it appeared in Excel.
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.
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.
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.
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.
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.
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 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 :
Total
AFF Mapper – Example

First Row
Headings
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.
CCode
CName
Data
countycode
countyname
Cases:data
Second
Row
Headings 26001
ALCONA
38
26003
ALGER
90
26005
ALLEGAN
81
26007
ALPENA
18
26009
ANTRIM
26
26011
ARENAC
33
26013
BARAGA
41
Note the colon :
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.

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 CNTY|DFP 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.

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.
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
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.

AFF Mapper – Example
Quick Recap
I want to
Map Community
Data
Find ready-to-use KML data
Convert from other data types
Use AFF Mapper
Map Case Data
Directly as points
on the globe/map
In aggregate form
using colors/shapes
Use a geocoder on the actual
address data & create KML
Use Earthplot or
AFF Mapper
To-Do
1.
2.
3.
4.
5.
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.
LSNTAP GIS Resources

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‘Lunch and Map’ open house same time next
week. Bring homework, bring questions,
answers, food…
Roundtables: Aug 13, Oct 8
Next Training series – Sep 11,18,25
GIS mailing list resurrected – do sign up and
participate https://lists.mayfirst.org/cgibin/mailman/listinfo/gis
GIS Resources section on LSNTAP.org updated
Set up a meeting with Madhu if you need
support. Email [email protected]