Short URL

Soil Survey Digitization and Mapping

 

Other Cartography/Mapping areas:

Loading, please wait...

The Arkansas soil digitization project started in 1995 when the Arkansas Legislature allocated funds to the Arkansas Natural Resources Commission  to digitize the soil surveys of the Mississippi River Delta of the 26 counties in Eastern Arkansas. This project was initially a cooperative venture between the Crop, Soil and Environmental Sciences at the University of Arkansas, the Natural Resources and Conservation Service (NRCS) in Little Rock and the Arkansas Water Resources Center at the University of Arkansas. The digitization of the rest of the counties in Arkansas continued until 2006 when soil surveys of all 75 counties in Arkansas were completed with the support of previous legislatures, the cooperation of the above mentioned agencies and organizations, including the Center for Advanced Spatial Technologies.

Traditionally, the results of a soil survey have been presented in hard copy publications that included maps and associated information in tables and narratives. More efficiently, the digital soil databases serve today all the purposes of the traditional soil surveys and much more. Some of the advantages of completing a state-wide digital soil databases are:
a) Provide county, city, state and federal governments, and other decision makers a digital soils layer that can be used with other data layers such as land use and land cover, aerial photographic imagery, topographic base maps and socio-economic data using Geographic Information Systems (GIS) in order to facilitate analysis and decision making;
b) Supply a more efficient and economical method for keeping soils information updated and available to users;
c) Offer cost savings by reducing the number of traditional hard copy soil surveys that need to be republished, as original supplies are exhausted;
d) Take advantage of computer technology to store and manage large quantities of soils data, which results in savings of time and additional expenses for county and state agencies;
e) Provide easy access to soils information that can be downloaded and captured for any area via the Internet;
f) Facilitate policy makers easy access to a critical, state-wide natural resource database to help the development and implementation of local and state policies related to environment and natural resources issues;
g) Assist County Conservation Districts, the Cooperative Extension Service, consultants and others to provide more efficient and timely assistance to farmers and other land managers when developing plans for animal manure management, soil and water conservation, pasture management, forest and site specific soil and crop management.

 

Soil surveys digitization process and products

The digitization of the Arkansas county soil surveys project at CAST was a continuation of the soil database development project in which soil surveys of the 75 Arkansas counties were digitized. This digitization project was completed at CAST between 2003-2006 and was intended to finalize the digitization of the remaining seven counties in Arkansas. The final products provided to NRCS were the digitized county soil survey maps, associated to relational databases, and digital maps of each county reflecting selected soil surface properties. These digital data represented the first step in the completion of the Soil Survey Geographic Database (SSURGO), as part of the National Soil Information System (NASIS). The project was completed at the Center for Advanced Spatial Technologies (CAST) with the financial support of the Arkansas Natuaral Resources Commission and in cooperation with the Natural Resources Conservation Service (NRCS).

The  following counties were digitized as part of this project: Bradley, Calhoun, Cleveland, Dallas, Ouachita, and Pike. The last soil survey to be digitized was Grant county, later completed by NRCS in Little Rock. Some of these counties, which are strategically situated into the West Gulf Coastal Plain area, had no published soil surveys. As a consequence, the digital soil information for these counties was of critical importance for a wide variety of professionals and public users.

The soil surveys were developed on mylars by NRCS personnel and the digitization was performed at the Center for Advanced Spatial Technologies. The quality of the digitization process is in accordance with the national cartographic standards.

Digitizing the soil boundaries consisted of three major stages. The first stage was of the creation and processing the soil maps, and also raster and vector editing of each individual map on a 7.5 minute quadrangle map. Stage two involved the joining of the quadrangle maps to provide seamless county survey coverage. Stage three included error-checking for each individual map and a seamless patch of the maps. NRCS was the agency that conducted the final checks on the overall quality of the work and had the final approval authority before submitting the soil survey for SSURGO certification.

 

 Example of the “check attributes” operation in LT2000®,
part of the digitizing process

“Edge match” operation in LT2000® during the digitizing process in which the edges of a polygon are connected across the neatline

 Project summary

In the last phase of the project 6 counties were digitized (Bradley, Calhoun, Dallas, Ouachita, Pike and Cleveland), joining the 68 previously digitized since the beginning of the Arkansas soil survey digitization project in the early 1990s. With the current digitization completed, 74 counties out of 75 were digitized by June 2005.

Grant County, the only one left for digitization, did not have a survey completed by NRCS at that time, but was surveyed, and digitized at the end of fiscal year 2006.

For the present digitization project the following products have been delivered for review to the NRCS office in Little Rock:

1) A complete, accurate and digital SSURGO database at a 1:24,000 scale for the following counties: Bradley, Calhoun, Dallas, Ouachita and Pike.

2) Cleveland county was delivered at a 1:12,000 scale as surveyed.

 All 75 county soil surveys of Arkansas are available for viewing at the NRCS Web Soil Survey and data is also available for download in various formats at  NRCS Soil Data Mart.