Soil Maps Command

A soil map is a geographic representation of the variety of soil types and/or soil properties (soil pH, textures, organic matter, horizon depths, and so on) in a given area. Soil maps are often used in projects involving land assessment, spatial planning, agricultural extension, environmental protection, and others.

When rain falls over land, a portion of it runs off into stream channels and stormwater systems, while the remaining water infiltrates into the soil or returns to the atmosphere directly through evaporation.

Physical properties of soil affect the rate at which water is absorbed and the amount of runoff produced by a storm. The hydrologic soil group provides an index of the rate at which water infiltrates a soil and functions as an input to rainfall-runoff models used to predict potential stream flow.

Displaying Soil Groups for Different Regions

The Soil Maps command of CivilGEO’s software allows the user to display global or regional (United States, Canada, Africa, and Europe only) soil maps on the Map View.

To display the soil map on the Map View, select the Soil Maps dropdown menu from the Map Data ribbon menu.

Note: The user needs to assign a coordinate reference system (CRS) to the project before assigning soil survey data. To learn more about the coordinate reference system (CRS), refer to this article in our knowledge base.

The following countries are listed under the Soil Maps dropdown menu:

• USA – This option displays the Soil Survey Geographic (SSURGO) maps by the United States Department of Agriculture's Natural Resources Conservation Service (NRCS).
• Canada – This option displays the national scale thematic dataset displaying the classification of soils in terms of provincial Detailed Soil Surveys (DDS) polygons, Soil Landscape Polygons (SLCs), Soil Order, and Great Group.
• Africa – This option displays the harmonized soil map showing the soil classes at the continent scale produced for the Soil Atlas of Africa. The map has been derived from the Harmonized World Soil Database (HWSD).
• Europe – This option displays the European Soil Database (ESDB), the harmonized soil database for Europe, also extending to Eurasia.
• Global – This option displays the Hydrologic Soil Groups (HYSOGs250m) with worldwide coverage for curve number-based runoff modeling. This dataset from the Oak Ridge National Laboratory Distributed Active Archive Center (ORNLDAAC) provides a globally consistent, gridded dataset of hydrologic soil groups (HSGs) with a geographic resolution of 1/480 decimal degrees, corresponding to a projected resolution of approximately 250 x 250 meters. These data were developed to support USDA-based curve-number runoff modeling at regional and continental scales.

Clicking on any of the countries listed above will cause the software to display the Soil Maps dialog box.

The user can click on the [OK] button to add the soil survey data layer of the selected region on the Map View. An example of NRCS soil survey data is shown below.

In the Map Data Layers panel, the software provides a data legend for each hydrologic soil group layer that lists the soil survey data included within that layer. The user can expand the layer to view the data legend.

Downloading Soil Survey Data as Shapefile Data

The Soil Maps dropdown menu contains one additional command: Soil Survey Data Download. This command allows the user to download hydrologic soil groups as shapefile data. Refer to this article in our knowledge base to learn more about the Soil Survey Data Download command.