Methods
Building a Hyperlinked List of Series Names
- Data Source: The Iowa Soil Properties and Interpretation Database (ISPAID) created by the Iowa Cooperative Soil Survey (ICSS) is a flat-file format database that contains 1 record for each soil mapping unit (SMU) that appears in NRCS county soil surveys for Iowa.
- The 10,634 ISPAID records were filtered in Microsoft Excel to create a list of 1565 unique mapping unit (MU) names.
- Series names were extracted from an alphabetically-sorted list of MU names using the Excel text function SEARCH. The extracted names were filtered to produce a list of 445 unique soil series names.
- An NRCS webserver stores Official Series Descriptions (OSDs) as html files, one per series, organized in folders A-Z according to the initial letter of the series. This file-naming convention allows Ackmore to Zwingle to use server-side scripts to build hyperlinks "on the fly" from series names stored in a web-enabled database.
Classifying Soil Names to Geologic Materials
- ISPAID identifies the parent material and landscape position of soils for individual SMUs. Values for these two variables are usually sufficient to classify SMUs to a geologic landform/sediment assemblage (LSA), or minimally to identify the geologic material in which the soil formed (loess, till, alluvium, colluvium, bedrock, or pre-Wisconsinan paleosols, hillslope sediments (pedisediments), and tills).
- LSA classifications were aided by previous classifications of ISPAID data compiled for parts of southeastern Iowa and the Des Moines Lobe by Deb Quade and others (Iowa Geological Survey). and for parts of western Iowa by Joe Artz. These lists, applied to ISPAID using the Excel VLOOKUP function, classified about 8000 of the 10,634 ISPAID records.
- The remaining SMUs, located primarily in northeast and northwest Iowa, were classified using ISPAID landscape/parent material variables and OSD information.
- The 147 soil series formed in Holocene alluvium were classified to DeForest Formation units using the above sources, ISPAID landscape position/parent material values, and taxonomic classification and horizonation data from OSDs. Michael Perry (Office of the State Archaeologist) assisted in the classification.
This is a generalized account of the methods used. Many of the procedures entailed intermediate steps of data cleaning and normalization. A complete account of process steps is available.
Version Log:
- v 1.0 (08/01/05). HTML version with hyperlinks to OSDs; not released to public.
- v 2.1 (09/12/05). ASP version, linked to database, with classifications by parent materials. Alphabetic menu and soil parent material menus display series subsets. Purpose, Appropriate Use, and Methods sections added.
- v 2.2 (11/23/05). Substantial reclassification of parent materials, particularly for upland series. Addition of checkboxes to display MLRA, Parent Materials, and Landscape Positions from ISPAID.
- v 3.0 (08/03/17). Redesign of website, including major changes to styles and layout. Content and linkage to OSD remains the same.