Thematic maps, spatial variability, mobile mapping systems and its application in precision farming

1. Lecture No.: 6

2. Thematic Maps
⦿ A thematic map shows georeferenced data, numeric or character, by
colours or symbols. Specific data displayed in this manner is referred to as a
theme
⦿ Different types of thematic maps, useful for showing different types of
thematic variables
⦿ Commonly used to show natural resources, vegetation areas,
population, types of soil, climate, temperature etc.,
⦿ A thematic map is a map that highlights a particular theme or
special topic such as the average distribution of rainfall in an area.

3. Thematic maps
• A thematic map shows the spatial distribution of one or more specific data themes for
standard geographic areas.
• The map may be qualitative in nature (e.g., predominant farm types) or quantitative
(e.g., percentage)
• Data's are visualize on the basis of spatial concepts, like density, ratio, percentages,
index numbers and of procedures like averaging.
• To make things comparable, the data's are relate them to standard units like square
kilometres, or convert them to standard situations.

4. Although cartographers can use these datasets in many different
ways to create thematic maps, there are five thematic mapping techniques
that are used most often.
1. Choropleth map
• This is a map that represents quantitative data as a color and can show
density, percent, average value or quantity of an event within a
geographic area.
• Sequential colors on these maps represent
increasing or decreasing positive or negative
data values.
• Normally, each color also represents a range
of values.
TYPES OF THEMATIC MAPS

5. 2. Proportional or graduated symbols
• Proportional or graduated symbols are the next type of map and
represent data associated with point locations such as cities.
• Data is displayed on these maps with proportionally sized symbols to
show differences in occurrences.
• Circles are most often used with these maps
but squares and other geometric shapes are
suitable as well.

6. 3. Isarithmic or contour map
• Isolines that represent continuous values like precipitation levels.
• These maps can also display three-dimensional values like elevation on
topographic maps.
Generally data for isarithmic maps is gathered
via measureable points (e.g. - weather stations)
or is collected by area (e.g. - tons of tomato per
acre by county).

7. 4. DOT MAP
• Is another type of thematic map and uses dots to
show the presence of a theme and display a spatial
design.
• On these maps, a dot can represent one unit or
several, depending on what is being painted with
the map.
5. Dasymetric mapping
• This map is a complex variation of the choropleth
map and works by using statistics and extra
information to combine areas with similar values

8. Data to display on a thematic map can be:
• Nominal: distribution of a phenomenon without a measurement. Label,
category. (Qualitative)
• Ordinal: Ranked data. High, medium, low or how much greater than.
(Quantitative)
• Ratio/Interval: how much different, measured by numbers. (Quantitative)

9. Spatial variability
• Spatial variability occurs when a quantity that is measured at
different spatial locations exhibits values that differ across the
locations.
• Spatial variability can be assessed using spatial descriptive
statistics such as the range.
• Spatial variability does not have to be ignored when managing
horticultural fields using precision farming techniques.

10. • Key applications where precision horticulture is used for
more efficient management of spatial variability include
variable rate application of fertilizer, herbicide, irrigation and
seed.
• These applications are intended to help improve the
efficiency of farm input applications, leading to improved
profitability and environmental quality.
Spatial variability

11. Mobile Mapping
• Mobile Mapping System is an information technology that has been
developed since late 1980s with the advance and progress in mobile
positioning technology, modern communication technology, spatial
information technology and embedded technology, etc.
• Integrating diversiform advanced technologies above-mentioned, Mobile
Mapping System is capable of real time data accessing, mapping and
spatial data visualization.

12. • Precision horticulture (precision farming, digital horticulture) has evolved
from a concept ten years ago into an emerging technology today.
• Its basic purpose is to manage farmland by the square meter instead of the
square mile.
• It is assured that precision horticulture can be described as the next great
evolution in horticulture.
• With Mobile Mapping System, every inch soil can be monitor and
planting data in detail can be acquired anywhere anytime.
Mobile Mapping

13. • Mobile Mapping System not only collects dynamic data about some object
in moving, but also manipulates these data in order to make decision
efficiently, and make these data be downloaded into a desktop GIS
simultaneously by wireless or wire communication as you like.
Mobile Mapping
• Now Mobile Mapping System has been applied in many fields, such as
intelligent transport, precision horticulture, field surveying and
environment engineering and so on for outstanding real time supply is
very essential in these fields and Mobile Mapping System can do.

14. Mobile Mapping System in Precision Horticulture
• For precision farming, information technologies are so essential that
Mobile Mapping System is important or beneficial.
• Equipped with mapping sensors and navigation sensors, Mobile Mapping
System can collect field data anytime, anywhere, in any manner.
• At the same time, Mobile Mapping System can connected with a GIS or
combine GIS software in its mobile terminals directly.
• Thus Mobile Mapping System can monitor planting process all along.
• Moreover it can contrast multi-temporal data collected or stored in
database and find what changes occurred, where, when and how, then
give an efficient plant plan.

15. Function of Mobile Mapping System in precision horticulture
Improve the Accuracy of Soil Sampling
• Accuracy of soil sampling refers mainly to accurate degree of the position
information where the soil samples were taken. With the accurate knowledge
about the coordinate location of the soil samples, a soil data layer can be
developed accordingly. With the accurate position information, navigating
back to those locations for re-sampling is possible.
• Mobile Mapping System has equipped navigation sensors, such as GPS and
INS, so the time and position information can be recorded at the same time
when soil samples are taken. Consequently a soil difference map can be create,
on which physical attribute of soil is described.

16. Plant Growth, Diseases and Insect Pests Monitor
• Generally precision horticulture is raised in a large area. Hereby it is
impossible for all plants growing in like manner.
• Sometime only a single part suffers the diseases and insect pests.
• Then it is unnecessary and even harmful for all plants to spray pesticide
or other medicine in the same way.
• Different solution should be taken according to the real conditions of
plants.
Function of Mobile Mapping System in precision horticulture

17. • Mobile Mapping System can finish the monitor task of all the plants.
• Using the scanners, the peculiar plants can be found quickly, and its
position also can be recorded.
• In fact satellite remote sensing data also can provide such difference
information.
• Compare with Mobile Mapping System, its spatial range is much larger
but space resolution is lower and forced by satellite calendar.
Plant Growth, Diseases and Insect Pests Monitor
Function of Mobile Mapping System in precision horticulture

18. Analysis of the Crop and Field Information
• The purpose to get so much data about the soil, plant and so on is to
master the planting conditions and to make decisions for all planting
process.
• Accordingly GIS and Agriculture Expert System are usually imported in
precision horticulture in order to edit, process, integrate and analyze the
crop and field information and get corresponding resolve scheme.
• Mobile Mapping System may Load multi-source information and different
types of horticultural data to master the conditions of the field.
Function of Mobile Mapping System in precision horticulture

19. • Comparing the information or data, relationships within and between
data sets can be found. That is the relationships among different factors
can be made certain. By the relation, agronomist or Agriculture Expert
System can make production plan.
• After the production plan has been made, farmers can command the
farming machines to work automatically, for these machines has been
equipped intelligent implement and positioning devices. Moreover the
entire process of one year farming also can be recorded and evaluated,
and the experience can be analyzed to help next year work.
Analysis of the Crop and Field Information
Function of Mobile Mapping System in precision horticulture