Integrating GIS Technology into the National Resource Inventory

Travis Rome

GIS Specialist

USDA Natural Resources Conservation Service

760 S. Broadway

Salina, KS 67401

Telephone (785) 823-4587

Fax (785) 823-4540

E-mail travis.rome@ks.usda.gov

This paper presents the use of a Geographical Information System (GIS) in the National Resources Inventory (NRI) which is conducted by the USDA-Natural Resources Conservation Service (NRCS). The NRI provides relevant information that is used to formulate effective agricultural and environmental policies and legislation, implement resource conservation programs, and enhance the public’s understanding of natural resources and environmental conditions. The paper focuses on the technology transition of the data collection process from a hardcopy environment to a digital environment for the 2000 NRI completed in the state of Kansas.

The NRI provides relevant information that is used to formulate effective agricultural and environmental policies and legislation, implement resource conservation programs, and enhance the public’s understanding of natural resources and environmental conditions. The Natural Resources Conservation Service formerly the Soil Conservation Service has been conducting resource inventories since the 1930’s. In 1982 a more comprehensive resource inventory was conducted called the National Resources Inventory (NRI), this inventory was done through onsite investigation of a random set of sampling units called Primary Sample Units (PSU’s). A typical PSU in Kansas is a tract of land approximately 160 acres in size, square or rectangular in shape. In 1987, the NRI was conducted with remote sensing being used to collect approximately 30 percent of the data. In 1992, the Primary Sampling Units were digitized into a GIS and aerial photography was used with map products produced from the GIS to do the data collection. The 1997 NRI was conducted by gathering data almost exclusively through remote sensing of aerial photography. The NRI was conducted every five years until 2000, when a continuous inventory strategy was adopted. In 2000 several states including Kansas purchased color digital ortho photography to use in the data collection process. This paper focuses on the technology transition of the data collection process from a hardcopy environment to a digital environment for the 2000 NRI conducted in the state of Kansas.

The objective of the 2000 NRI in Kansas was to utilize digital images in a GIS to perform the data collection process of the resource inventory. Other objectives are listed below:

• Use existing staff to perform the data collection. These staff members typically have many years of field experience and also have experience in photo interpreting color photography.

• Maintain or increase the speed of the data collection process.

• Increase the accuracy of the data collected.

• Increase the consistency of the data being collected from one year to the next.

In the 1992 National Resource Inventory PSU’s were compiled to and digitized off of USGS 7.5 minute topographic maps. Individual PSU maps were printed on transparencies at a scale of 1:7920, these maps are called PSU support maps and were used as the base map for data collection.

Color aerial photography was flown, converted to slide and labeled for each PSU.

Data collection worksheets were sent to NRCS field offices for each PSU to collect onsite information.

The following support materials were gathered for each of the PSU’s: a photocopy of the soil survey, a USGS topographic map, a photocopy of black and white photography containing farm program information from the Farm Services Agency, a data collection worksheet from a NRCS field office, and a copy of the PSU support map from the previous inventory.

The color aerial photography was placed into a slide projector and projected down onto a PSU support map where the following features were delineated and labeled: farmsteads and ranch headquarters, small built-up areas, large urban and built-up areas, large streams, small streams, large water bodies, small water bodies and transportation corridors. Resource information collected through remote sensing was documented on the data collection worksheet.

The features delineated on each support map were carefully measured using a digital planimeter. The measurements were recorded on the support map and subsequently entered into a database.

The Natural Resources Conservation Service has staff with many years of experience in photo interpreting color photography. To take advantage of this experienced workforce a user friendly photo interpretation/data collection tool was needed. Arc/Info and the Arc Macro Language (AML) were used to create the tool with a very specific function requiring a low learning curve. Naming conventions and directory structures were developed so that the data collection tool could be written in such a way that the photo interpreters would not have to have previous experience using GIS do their job. Since the data being collected by the photo interpreters was very specific, buttons and popup windows were developed within the tool to do attribution of data simultaneously with data collection. A report generating AML and a map generating AML were also written to export the collected data in report and map form. Color digital ortho photography was acquired for the primary sample units. Accuracy of the new digital photography was assessed by comparing it to an earlier flight of ortho photography that originated from USGS. The new digital photography was determined to meet the accuracy standards needed to conduct the inventory.

Ortho imagery is acquired and checked for accuracy.

Data collection worksheets are sent to NRCS field offices for each PSU to collect information on items that cannot be gathered through photo interpretation. These items include, ownership, crop residue levels and conservation program information.

Support materials are converted to a digital format through scanning to increase efficiency of the on screen data collection and reduce paper handling.

The statewide ARC/INFO coverage of PSU’s for Kansas is tiled into county coverages.

Training on the use of the photo interpretation/data collection tool is given to photo interpreters. Most of the photo interpreters require only a few hours of training.

The data collection tool is used to perform on screen digitizing of the following features: farmsteads and ranch headquarters, small built-up areas, large urban and built-up areas, large streams, small streams, large water bodies, small water bodies and transportation corridors.

The photo interpretation/data collection tool generates and prints a PSU support map for the file.

The photo interpretation/data collection tool generates a report on the features for the PSU. Data then is manually entered into a database along with the information gathered from the NRCS field office.

The goal of this project was to transition the National Resource Inventory from a hardcopy environment to a digital environment through the use of GIS while utilizing existing staff with little GIS experience. The goal has been met with many benefits realized. Through the use of the photo interpretation/data collection tool accuracy was increased due to the inherent measurement accuracy of GIS and elimination of scaling errors that were present in the previous technology. PSU support maps and data collection reports are byproducts of the data collection, and generated without any extra effort. Support maps and data collection reports are of higher quality than in past NRI’s. Data collection speed has increased by employing GIS technology. Future inventories will see greater increases in data collection speed as data layers collected and stored in GIS are utilized. Photo interpreters enjoyed using the new technology to do their job because it is easy to use and it eliminated the dark room environment required by the previous methodologies.

I would like to acknowledge the following people for their support in developing this project.

Larry Kuder, Inventory Collection and Coordination Site Leader, NRCS Salina, KS

George Rohaley, Acting Director of the Resources Inventory Division, NRCS, Beltsville, MD

Dean Thompson, NRI Program Leader, NRCS Statistical Laboratory, Ames, IA