GLIS Project Description
by Dan Harms
August 22, 2006
Jo Daviess County Prairie Site Evaluation
School: Jo Daviess Carroll Area Vocational Center
Student: Margaret Grommes
Instructor: Dan Harms
Margaret Grommes entered the Jo Daviess Carroll Area Vocational Center as a junior from River Ridge High School in Northwestern Illinois knowing she was interested in continuing her education beyond high school in some challenging field. She signed up for the Computer Aided Drafting and Geographic Information Systems class as a stepping-stone to engineering, one of the career areas she was considering. Part of the mission of the Jo Daviess Carroll Area Vocational Center is to allow students to “try out” career areas prior to committing time and money to a college degree.
The Area Vocational Center’s individualized competency-based system allows students to try a number of fields and to then specialize in areas they find most interesting. As a first year student, Margaret experienced mechanical drawing, architectural drawing, civil engineering technician skills, and GIS. When she returned as a high school senior for her second year, she was asked to identify an area of specialization. Margaret’s farm background, interest and affinity for mathematics, and experience in the CAD/GIS class lead her to look at pursuing a career in civil engineering with an emphasis on natural resources, soil and water conservation, and environmental engineering. By the time Margaret entered her senior year in high school she had started to look at engineering schools in the region that could meet her interests.
As a second year student, Margaret planned her course of study with Mr. Harms, CAD/GIS instructor at the AVC. Based upon her career goals and interests they planned a program designed to equip her with skills that would enhance and augment her college career. Margaret had gained experience with AutoCad and ArcView 3.2, as well as working with various types of data and drawings in her first year in the class. For the second year Margaret and Mr. Harms planned a program that concentrated on skills in civil engineering and GIS working with ArcGIS, AutoDesk Map, and AutoDesk Landdesktop.
Second year students in the AVC CAD/GIS class are also expected to participate in community-based learning by participating in an internship or a community based in-school project. During the Fall of 2005, a newspaper article concerning the goals of the Jo Daviess Conservation Foundation caught Mr. Harms’ eye. One of the stated goals was to identify prairie remnants in Jo Daviess County, Illinois. This seemed like an ideal area for a community-based project using the GIS technology and capacity of the AVC, the learning objectives of a motivated student, and the goals of a local non-profit organization.
The Jo Daviess Conservation Foundation (http://www.jdcf.org/) is a non-profit organization committed to protecting the natural heritage, spectacular scenery, and agricultural character of Jo Daviess County. The Jo Daviess Conservation Foundation partnered with the Northwest Illinois Chapter of the Prairie Enthusiasts (http://www.theprairieenthusiasts.org/chapter/ill/nwill.htm) in the prairie site identification project.
Mr. Harms and Margaret met with Chris Kirkpatrick; Land Protection Specialist for the Jo Daviess Conservation Foundation and Jim Rachey of the Northwest Illinois Chapter of the Prairie Enthusiasts to see if a project could be developed. Based upon the needs and the expertise of the parties a project plan was developed that outlined the following objectives:
a. Develop a dataset that could be used by Chris Kirkpatrick as a tool to identify possible prairie remnant sites in Jo Daviess County, Illinois.
b. Base the data sets upon historical land use data from the Illinois State Library and Illinois Natural History survey
c. Combine county ecosystem data in the possession of the Northwest Illinois Chapter of the Prairie Enthusiasts with modern SSURGO data for the county
d. Use DEM data to create aspect data to identify topography most likely to support prairie remnants.
e. Georeference all of the data so GPS points could be pulled from the data to do field location studies, and to allow the plotting of GPS points from field observations.
The first step was to accumulate the data. The Northwest Illinois Prairie Enthusiasts provided tables matching soil types with ecosystems. The SSURGO (soil map) data for Jo Daviess County Illinois was downloaded from the USDA’s site (http://soildatamart.nrcs.usda.gov/). Contemporary land use data was downloaded from the Illinois Department of Agriculture (http://www.agr.state.il.us/gis/index.html). USGS DEM data for the Jo Daviess County quadrangles was downloaded from Geocommunity (http://data.geocomm.com/dem/demdownload.html). One of the important data sets, Landcover of Illinois in the Early 1800’s had been obtained by Mr. Harms from the Illinois Natural History Survey and was on file as part of the data at the AVC. This data can be viewed on line at: (http://www.inhs.uiuc.edu/cwpe/maps/glo.html). Tigerâ data from the U.S. Census Bureau was used to get the basic shape of Jo Daviess County. Tigerâ in ESRI shapefile format was downloaded through the ESRI website. (http://arcdata.esri.com/data/tiger2000/tiger_download.cfm)
One of the principle objectives of Margaret’s project was to develop GIS layers that could be delivered to the client (Jo Daviess Conservation Foundation) in a format that could be used by the client. At the time, the Jo Daviess Conservation Foundation was equipped with ESRI ArcView 3.2 so the data had to be compatible with this system. Raster data had to be delivered in a format viewable by ArcView 3.2, and data had to be reprojected to decimal degrees so that it could be used as base maps by the foundation. The diversity of data made for a challenging project, but a project with problems that might typically face a GIS technician, one of the fields Margaret was considering.
Once the data was collected Margaret used a workstation equipped with ArcView 3.2, ArcGIS 8.0 (ArcMap), Spatial Analyst for ArcGIS, Micro Soft Access and AutoDesk Map 2005. With the help of Mr. Harms, whose background in natural resource management provided expertise, Margaret began learning about the history, agronomy, soil science, and ecology of her home.
One of the goals was to take the ecosystem tables provided by the Prairie Enthusiasts and map them to soil types. The data was delivered as printed sheets listing soil types by MUSYM (number) and an ecosystem code. The first task was to create a table from this material. The printed sheets were scanned, the text captured and converted to a comma delimited text file (csv). This data was converted to a table using Micro Soft Access. Inspection of the tables from the ecosystem data and the SSURGO data showed a mismatch between the MUSYM numbers for the soils. Margaret developed a table to match the appropriate soil designations. Once the tables were completed, the tables were joined to produce an ecosystem map based upon soil types. This map is valuable as a tool to identify expected sites of prairie remnants.
One of the richest data sets available for this project was the USDA SSURGO data. Since the ecosystem data provided by the Prairie Enthusiasts was linked to soil types it made since to investigate this data further. Margaret researched soil taxonomy, specifically the soil orders and identified the role of native vegetation in soil development. By mapping the soil orders in Jo Daviess County, specifically Alifisols and Mollisols another tool for identifying the native vegetation (either grassland or forest) of the region was developed.
An important part of identifying potential prairie remnant sites is historical data. The Illinois State Library and the Illinois Natural History Survey have produced a statewide land cover map based upon the Federal Land Surveys done during the 1800s. Mr. Harms had a copy of this data on file at the Area Vocational Center. The data, in ArcInfo Export (.e00) format was loaded into ArcMap, and Jo Daviess County clipped from the statewide data using a Tigerâ data basemap of the county. The resulting layer was then reclassified to give a representative map of observed land cover from the early 1800s.
In discussions with Mr. Kirkpatrick it was discovered that already discovered prairie remnants tended to be on the south and southwest slopes of the hills of Jo Daviess County. To develop a layer that would allow analysis from aspect standpoint, a mosaic of USGS DEMs was created using Spatial Analyst. This process was complicated by the fact that some of the DEMs had the meter as the base unit, while others used feet. Another complication is that Jo Daviess County lies in two UTM zones, 15N and 16N. Since the source DEMs were in UTM projection many had to be reprojected to create a uniform map. (Zone 16 DEMs were reprojected to zone 15.) Once the mosaic had been assembled, Spatial Analyst was used to create a hillshade. The hillshade image was used as a base for an aspect image also created from the DEM mosaic. The aspect map was reclassified so that the south and southwest slopes were highlighted on a visual map.
A current (2000) land cover map for the county was developed using data downloaded from the Illinois Department of Agriculture. This statewide data in the form of an ESRI Grid had to be resampled to create a map of Jo Daviess County. The map symbology was recalculated to show the distinctive land uses based upon the Class_names included with the ESRI Grid.
A large amount of data, from various sources had to be combined to create this project. The precision and accuracy of the project varies with the layer’s source data. The metadata of each original data set was used to determine the accuracy and note it, and Margaret developed metadata for each of the layers she derived through her analysis. The SSURGO data is not recommended for use in areas less than 5 acres, and was the base data for several of the maps. The historic land use data was derived from hand drawn field notes made in the 1830s and 1840s. No reasonable estimation of precision or spatial accuracy can be made other than observation of still existing features on or near the Public Land Survey lines surveyed originally. The USGS DEMs used for this project were developed from USGS digital quadrangle maps with 20 foot contour intervals. In this use, which only relies upon general aspect the vertical accuracy is not an important factor. The current land cover data is based upon 30 meter resolution raster images and therefore not recommended for map scales larger than 1:100,000.
This project is a tremendous example of the strength of GIS as an excellent learning tool. In completing this project Margaret not only became very familiar with GIS software and the supporting software like Micro Soft Access, she also became very familiar with data sources and formats. To complete the project Margaret had to investigate many other fields, including the history of the public land survey system, soils and ecology, and the history and ecology of northwestern Illinois. As a capstone project, Margaret was encouraged to use skills in math, communication, and science, skills that she had gained in other classes during her high school career. She also had the satisfaction of knowing that her research and work was needed and would be used by the community. Margaret is continuing her education in civil engineering at the University of Wisconsin, Platteville.
