This document discusses the process of automating the creation of hypsometric areas from contours. Hypsometric areas represent the area between two neighboring contour lines and show the elevation of terrain through graduated color schemes. The author outlines challenges in building polygons from contours, assigning minimum and maximum elevation values to each polygon, validating the output, and validating hypsometric area attributes. A custom transformer was created to automate this process and is available on the FME Hub.

1. Greg Patterson
+61 400 231 518
Teacher (Spatial Information): CIT
Senior Research Officer (GIS Specialist): ANU

2. Hypsometric Areas
Contours Hypsometric Areas
Automate the process of creating hypsometric areas from contours to
areas with minimum and maximum values.
Greg Patterson
+61 400 231 518

3. Hypsometric Areas
Hypsometric Areas (the area between two
neighbouring contour lines) represent the
elevation of the terrain.
The colours are normally shown as bands of
colour in a graduated scheme. A typical scheme
progresses from dark greens for lower elevations,
up through yellows/browns and on to greys and
white at the highest elevations.
Hypsometric Area tinting uses on maps and
globes is often accompanied by a similar method
called bathymetric tinting that represents the
depth of oceans. lighter shades of blue represent
shallower water and darker shades deeper
regions. Greg Patterson
+61 400 231 518

4. Custom Transformer
The workspace was converted
into a custom transformer for
other users to utilise. This
workspace will be available on
the FME Hub
Elevation:
The contour header that contains the
elevation (Height) values
Grid Size:
The grid interval required
Contour Interval:
Interval of the input contours
Hypsometric Areas
Greg Patterson
+61 400 231 518

5. The Custom Transformer
Workspace
Hypsometric Areas
Greg Patterson
+61 400 231 518

6. Hypsometric Areas
Challenges:
1. Build the contours for polygons
2. Assigning Minimum and Maximum values
3. Validate Output
4. Validate Hypsometric Values
Greg Patterson
+61 400 231 518

7. Challenges:
Build the contours for polygons
Issues identified:
a. Using the ‘BoundingBoxAccumulator’
Transformer, I noticed that not all contours
touched the extents of the bounding box
therefore had to use the ‘GeographicBufferer’
Transformer and buffer the bounding box
inwards to ensure that all contours
intersected the boundary area.
b. Adjacent polygons having the same elevation
value
Hypsometric Areas
The ‘HullAccumulator’ Transformer did not work as I hoped.
Greg Patterson
+61 400 231 518

8. Assigning Minimum and Maximum
values - Part 1
This process was completed using a few methods
a. Create a single point on the contour lines and
convert these point into a linear feature 0.01m in
size at 90 degrees to the contour lines.
b. Convert the ends of the lines into point.
Hypsometric Areas
Greg Patterson
+61 400 231 518

9. Assign Minimum and Maximum
values – Part 2
Create the gridlines in the East-West and North-
South direction
a. Create a single point on the contour lines and
convert these point into a linear feature 0.01m in
size at 90 degrees to the contour lines.
b. Convert the ends of the lines into point.
Hypsometric Areas
Greg Patterson
+61 400 231 518

10. Assign Minimum and Maximum
values (Part 3)
Process the isolated polygons (highest / lowest
points), internal and around the edges adding the
minimum and maximum values.
Note: The polygons around the edge may be incorrect
and will need to be validated with surrounding
contours if available.
Hypsometric Areas
Greg Patterson
+61 400 231 518

11. Challenges:
Assign Minimum and Maximum values (Part 4)
Last step was to identify the maximum value when only the minimum value was identified on
some of the area polygons
Hypsometric Areas
Greg Patterson
+61 400 231 518

12. Validate Output
This step was to validate the
number of areas created at the
start of the process to ensure that
they match the number of
Hypsometric Areas created.
Hypsometric Areas
Greg Patterson
+61 400 231 518

13. Hypsometric Areas
Validate Hypsometric Area
Attribute
The final step was to check that all
hypsometric Areas have the correct
minimum and maximum values.
If all areas are correct, then no features
should pass through these transformers.
If features pass through, this indicates that
there are errors with the original data:
1. Missing contours
2. Incorrect Contours
Greg Patterson
+61 400 231 518

14. Hypsometric Areas
Uses:
Analysing the following:
• Landforms
• Watershed / River basins
• Erosional Topology
• Glacial Features
• Soil and Water Conservation
• Climate Change
• Slope
• Flooding
Validation:
• Original contours
• Features located within the correct hypsometric
areas:
• Spot elevations
• Horizontal control points Greg Patterson
+61 400 231 518

15. Greg Patterson
+61 400 231 518
Thankyou !
ACKNOWLEDGEMENTS
I would like to take this opportunity to thank Safe Software Canada for their ongoing support
and for providing licences to the Canberra Institute of Technology that are used within the
training labs and take home licences for the students studying the Diploma of Spatial
Information Services.