Developing A Soil Survey of the Future
Thomas P. D'Avello
The traditional soil survey reports are the product of the
most comprehensive natural resource inventory in the
world. The format of the report has been static for many
years. This media and format can be cumbersome to use
and information can be difficult to find. The goal of a soil
survey is to provide quality information for land use
planning and management. Any limitations regarding ease
of use and understanding hamper this goal. Advances in
desk-top GIS technology and meetings with users led us
to development of a prototype soil survey on a
CD-ROM. ArcView2.1, Avenue and ArcView
Publisher are being used to create an interactive soil
survey, SoilView, that users can navigate with minimal
training. This paper will present the concepts, design and
features of the prototype application.
BACKGROUND
The traditional soil survey reports developed through the
United States National Cooperative Soil Survey
Program, are the product of the most comprehensive
natural resource inventory in the world. The format of the
report has been unchanged for the past 40 to 50 years
consisting of a bound document with three major
sections:
This media and format can be cumbersome to use,
requiring the user to shift back and forth between a
map(s) of interest and corresponding non-spatial data In
addition, many of the terms and concepts used in the
report are unfamiliar to many users (Valentine et al.
1981). The goal of a soil survey report is to provide
consistent, reliable information on the pattern of
occurrence and behavior of soils for multiple land uses
and management. Any limitations regarding ease of use
and understanding hamper this goal.
CURRENT STATUS
There is a soil survey for most of the 3,000 plus counties
in the United States. However, the scale, base map, and
classification system used varies from county to county.
The current emphasis is to bring consistency to the soil
survey across political boundaries using the knowledge
gained from the past 100 years (Indorante et al. 1996).
All soil surveys will now be done using USGS digital
orthophotographs at 1:12000 or 1:24000 scale as a base
map, all text, tables and spatial data will be in digital form
and archived as ASCII text, delimited ASCII text and
DLG3 Optional file formats respectively. Availability of
the digital data will be through the Natural Resources
Conservation Service (NRCS) National Cartographic
Center or State Office.
IS THIS ENOUGH?
Even with the digital emphasis we were still concerned
that we would not be meeting the needs of most of our
users. Formal and informal meetings and user surveys
confirmed our suspicion:
- Most users don't have $1,000 to $20,000 tied up
in GIS software/hardware
- Those that do, don't always have a day or two to
import/manipulate data
- Users would prefer to have a digital product that
comes ready to use.
WHAT USERS WANT
Many people are familiar with and use CDROMS,
multi-media educational software, World Wide Web
browsers etc. Once these products came on the market,
the thought of creating an interactive, multimedia soil
survey took hold. With funding from the NRCS National
Soil Survey Center, we started our journey towards
creation of an interactive digital soil survey with the
development of a wish list of features that included:
- Run under Windows
- Pure database capability
- Have links between maps tables, and text
- Map manipulation via database manipulation
- Hyper-links for graphics and text
- View multiple map "sheets" as one image
- Photographic background
- Easy to Use.
A review of available software led us to ArcView2.1 and
ArcView Publisher as the products that met all of the
user requirements.
SOILVIEW
Data Preparation
The desire was to include all of the data for a soil survey
on one CD. In order to accomplish this, some data
manipulation was required, primarily with the digital
orthophoto quarter quads, whose size averages 50
megabytes each. The digital orthos were resampled from
1 meter to 5 meter resolution using the cubic convolution
method, and trimmed at the 3.75' neatline, reducing their
file size about 96%, while maintaining reasonable spatial
resolution. Tab delimited ASCII tables were extracted
from the NRCS map unit interpretation record (MUIR)
tables, normalized and converted to "dbf" files. The text
data was converted into a stand-alone hyper-media
document, while soil coverages were converted to
shapefiles.
The Interface
Users of soil surveys want to determine information on
the attributes of a soil(s) or determine the spatial extent of
a soil attribute(s), or both. In gathering this information
users most often start from a map and proceed to a table
or text, and occasionally employ the inverse of this
method. SoilView allows the user to pursue either route.
SoilView uses a customized project with fewer
buttons/tools, unique menus and several customized
tools, with the goal of making the software as easy to use
as possible without limiting the essential functionality
required to utilize the survey. Our findings indicated that
most users are not, nor ever will be GIS gurus.
As part of the project start-up, all tables, text, and a
predefined view of the soil index map become available.
Once a user opens the "County View" view , they may
select a particular soil map by using a tool created called
"Select-by-point", or "Select-by-rectangle" (Figure 1).
Figure 1. Soil survey index map.
Scale dependent display of the shapefiles for the quarter
quad views is set at 1:30,000 to reduce drawing time and
clutter. An example of a view showing the interface will
give you an idea of what menus/buttons/tools are
available (Figure 2).
Figure 2. View of soil map.
The following close-up with the digital orthophoto as a
backdrop will give you an idea of the spatial resolution of
the image. Given the choice, our reviewers would rather
have higher resolution imagery, but not at the expense of
system performance or file size limitations (Figure 3).
Figure 3. Zoomed in view with orthophoto backdrop.
Tabular data is available almost as a user would find it in
a soil survey report, with a few exceptions. For example,
tables in the hard copy soil survey lists data ranges as
one data field for certain properties like pH, permeability
and water table depth. SoilView maintains the original
MUIR table structure, which has a data field for both the
minimum and maximum values of a given soil property.
An example of the "Soil and Water" table follows (Figure
4).
Figure 4. Portion of Soil and Water Table
The text of the soil survey is available from the menu as a
stand-alone hyper-media file, and functions like a
Windows Help file with pop-up windows, and
hyper-links to other text or graphics.The following two
figures give an example of the text capabilities (Figures 5
and 6).
Figure 5. Sample of soil survey manuscript window
Figure 6. Soil map unit description and hypertext Legend
Where the project is now?
The alpha release was reviewed by 10-15 people during
the months of January-March, 1996. Work on the beta
release, and the funding of it, will be complete by June,
1996. Several features that will be attempted to
incorporate in the beta include:
- Generic layout capability
- Query save/re-execute capability
- Hyper-links from the text to tables
- Hot links for soil series and map unit descriptions
What's ahead?
All of the responses received from review of the alpha
release were very favorable, in terms of ease of use, and
more importantly, the concept of providing the user a
bundled package of software and data. This product
could reduce the time between completion of field work
for a survey and publication an estimated 4 to 6 times.
We will be proposing this product as an additional and
preferred means of publishing soil surveys for the NRCS,
and hope to pursue additional enhancements of this
product.
ACKNOWLEDGMENTS
This work was supported in part by the NRCS National
Soil Survey Center. Avenue programming performed by
Scott Eichman and Dan Schreiber, Global Information
Systems Technology, Inc. , 100 Trade Center Drive,
Champaign, Illinois 61820 (217-352-1165).
REFERENCES
Indorante, S.J., R.L.McLeese, R.D.Hammer,
B.W.Thompson, D.L.Alexander. 1996. Positioning soil
survey for the 21st century. J.Soil and Water
Conservation 51:21-28.
Valentine, K.W.G., W.C. Naughton and M. Nava.
1981. A questionnaire to users of soil maps in British
Columbia: Results and implications for design and
content. Can.J. Soil Sci. 61: 123-135.
Thomas P. D'Avello
GIS Specialist
USDA-Natural Resources Conservation Service
2118 W. Park Court
Champaign, IL 61821
217-353-6637
E-mail: tom.davello@il.usda.gov
| 
About Us
Back to Top