2. Why are attribute tables
important?
Attribute tables define the elements of a
shapefile and allow you to see what is
“inside” the layer. They also allow you to
zoom, highlight and select for other
operations.
3. “Flat File” with columns and rows
Row = geographic feature record
Column = attribute field (item of
information about a feature)
4. Attribute field general types
• Numeric (integer or decimals)
• Text (string)
• Date
• Blob (binary large object)
Source: http://www.esi.utexas.edu/gk12/workshops/gis/ppts.php
11. JOIN
• Basic to all GIS programs is “joining”
• This is how tables of data (excel, csv,
etc) are transformed into maps
• For example, HIV prevalence by
province
12. Change data form
Must change the data format from EXCEL
or other database into a form that QGIS
can use
• The easiest process is using .dbf
• .dbf is an “old” data file type (dbase)
BUT shapefiles contain .dbf file data
which is why we use them
• To convert we need LibreOffice
13. LIBRE OFFICE
• Open Libre office and open your excel
data (name of excel file or type of data)
15. View the data you want to add..
Save as “name”.dbf inside data
folder
16. Open or maximize QGIS
• You will now add your .dbf file that you
created in Libre Office to the map layers
you are already displaying
• Click on “add vector layer”
19. Open “attribute layer” for
moz_adm1
• Find the column that has the name of
the provinces in it.
20.
21.
22. JOIN in QGIS
• Double click on moz_adm1
• When layer opens click on “join” tab
23.
24. 11.You will see this. Note
default target field ID_0
2. You MUST change target
field!
You need to match “like” with “like” so if you have province
data, in this case provincia, you must match with QGIS’s
province layer, in this case NAME_1.
34. Now make
sure to
change the
column so it
is set to the
file with
prevalence
that you
wish to
map. You
DO NOT
want
Column set
to ID_0
which is the
default. It
will crash
your
computer.
35.
36. How to change the
classification
Double click on a row to
begin. Be sure to select
“label” afterward to ensure
that your changes are
reflected in your labels. This
is also an opportunity to
simplify the label
presentation.
43. How to map a second
presentation of prevalence
onto one map: using symbols
• This step shows you how to map a
second level of prevalence, HIV
prevalence in men (MHIVPREV) onto a
map where the colors of provinces
represent the HIV prevalence of women
44.
45. Here is the final map
with the male and
female HIV prevalence
Male HIV
prevalence is
represented as
the pink dots and
female HIV
prevalence is
represented
within the blue
shaded province
layers.
46. Now go back to the diagram
layer, where you see pie chart
and choose text diagram.
What do you think?