Objectives
Hydrologic Land Cover Maps (HydroLCM) are remote sensing products
used to display land cover (and in some cases land use) for urban
and rural areas to support and enhance the application of hydrologic
modeling. HydroLCMs were developed in response to the need by local
government of updated information about trends in urban growth,
to locate and monitor new urban developments and stage of construction,
to derived the data needed for flood zone determinations and other
planning purposes. A major consideration in developing HydroLCMs
was to evaluate to what extent high-resolution satellite images
could replace total or partially aerial photographs as information
data source. The conclusion was that aerial photographs still couldn’t
be replaced for applications that require spatial resolutions of
less than 1 meter. However, because of the cost of aerial photo
surveys and map production, satellite images can effectively replace
them for map updates or for frequent monitoring of urban and land
cover changes.
User Community
The user community for HydroLCMs consists of local government
managers and engineers, consulting firms, utility companies and
private citizens.
Product Development
This product has been continuously developed since the start of
the Synergy program to respond to application requirements. As
land cover changes in the urban environment due to human activity,
there are also changes such as those indicated by the vegetation
that are seasonal. A major difference is observed when land cover
is mapped during the summer, when all trees have their leaves on,
as opposed to the winter when deciduous trees have no leaves and
the image data shows the ground cover. The Synergy program allowed
for the acquisition of Fall images and the resulting land cover
map was quite different from the Spring land cover mapped for Synergy
I. The availability of Ikonos data for two different seasons provided
an additional insight into the land cover mapping problem and allowed
for the development of change detection products applicable to
hydrology, environmental quality control and other applications.
HydroLCMs are produced by supervised classification of Ikonos
multispectral data using a two-step approach. Initially the data
is classified into 18 classes: woodland, mixed woods, grassland
types 1 and 2, soil types 1 though 5, water type 1 (clear),
water
types 2 and 3 (turbid), rooftops types 1 and 2, concrete types
1 and 2, asphalt. Some of these classes are combined to produce
the 7 classes used for most hydrologic applications: woodland,
mixed woods, grassland, soil (construction), soil (agriculture),
impervious, water. In some datasets it was necessary to include
a shadow class.
Experience of User Community
The experience of the user community with HydroLCMs still is rather
limited. Land cover mapping results at this time are still used
as an intermediate product to produce data used in hydrologic modeling,
environmental quality control and other applications.
Potential Activities for Synergy III
Synergy III will provide the opportunity to create new products.
These include:
a) Land cover maps that will provide the user with information
about the dynamic aspects of the Earth’s surface such as
seasonal changes of land cover;
b) Hydrologic land cover maps using merged Ikonos 4- and 1-meter
resolution datasets;
c) Land cover map produced for the airborne digital image 1-m data
Funding Support
This research was funded solely by Raytheon Synergy (100%).
 Figure
1. Top: Urban land cover map with 18 classes mapped for part of
southeast Columbia.
Bottom: Hydrologic land cover map with 7 classes mapped for same area.
Participants
Aderbal Correa and Janggam Adhityawarma
Center for Environmental Technology
Department of Civil & Environmental Engineering
University of Missouri-Columbia
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