Downloading soils information

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If your area of interest is in the USA, you can use GeoAgro GIS to download soils information directly from the USDA Web Soil Survey, using the WFS Tool.

WFS stands for Web Feature Service, and Open Standard that allows to retrieve geographic features from online servers - you may visit this WFS Article for more information.


Setup a sample project

For these exercises we are going to download a sample dataset: 'Sample Farm IA' and create a new project, or just open the project if you have previously created it.

For this purpose, you can follow the steps detailed in Download sample data, selecting 'Sample Farm IA' as the initial dataset, which can be found under the 'Tutorials_en' folder:


UDT1.jpg


Download Soils from the web soil survey

  1. First, double-click on the 'Fields_NRCS' layer to zoom to the layer.
    Image:CNMP_Planning_10a.jpg

    Please note:
    When downloading soils, it's convenient to keep the project area as small as possible, to make the soils download faster

  2. Select the “Soils” layer, under the Base Map group, to make it active:
    Locate and pan over your planning area

  3. Click on the “WFS” tool to connect to the soil survey Locate and pan over your planning area
Warning Warning: There is a current issue when downloading soils from USDA servers, which is that it donwloads soil map units from an area moved to the southwest from your current view. As a workaround, Pan the view moving it to the southwest, just before downloading soils.

  1. In the Importing window, click on the star button to see which servers are available.Locate and pan over your planning area Now, select “NRCS Soils WGS84 Geographic”.
    Locate and pan over your planning area

  2. The “Layer” dropdown menu shows which layers in the service are available for download. Select “MapUnitPolyExtended”.
    Locate and pan over your planning area
  3. In "Unique values field", select "OBJECTID"
  4. Click on “OK” and wait for the download to complete.Please note: If the downloading bar does not show any progress, it might be due to the WFS server not responding. Cancel your download and try again.
  5. Your project should look like the screen below
    Click here to see it full size

Warning Warning: Save your project: Use the Save Map GIS gis Edit 11 01.jpg tool to save your project. This is required after you download Soils info to update your project. Otherwise, there is a known issue that will give you a system error, and you'll have to close and re-open the project to fix it.


Clipping your soils to a field

To clip soils map units to a specific field, we are going to use the Copy Soil Survey tool Image:GIS_gis_Edit_22_01.jpg , which allows to generate a new polygon layer, by taking an existing soils layer and clipping it using a selected object of another layer as the clipping boundary.

This tool is commonly used for creating soils map units within a field, based on downloaded soils features from the web soil survey


CSS1.jpg


To clip an existing soils survey layer to a field, you can follow these steps:


1. Select the field that will be used as the clipping boundary

Make the Fields_NRCS layer active by clicking on it

CNMP Planning 10a.jpg

Use one of the Selection tools and select the field that will be used as the clipping boundary, as shown in the figure below:
CSS3.jpg

















Note Note: If there is an object selected, the Copy Soil Survey Tool will be available. Otherwise, it will be disabled.


2. Run the Copy Soil survey tool

Click on the Edit objects panel Image:GIS_gis_Edit_05_01.jpg, and Select the tool Copy soil survey 'Image:GIS_gis_Edit_22_01.jpg, the following window wil pop up:

Image:GIS_gis_Edit_22_02.jpg














1. No. of Objects: shows the number of selected objects. In this example we have 1 field selected that will be used to clip the soil survey.

2. Soil survey:  in this list, you need to select the layer in which the soil survey is located. In this example it's the 'Soils' layer.

3. Target Layer:  Shows the layer where the resulting polygons will be saved. You can choose between an Existing layer or a New layer.

If you choose the New layer option, when you click on the Green Cross to create the New layer, the new layer window will pop up (learn more about Creating a Vector Layer).

Enter the following values:

* Name: F4_Soils (as a standard, we adopt for instance a prefix F4, to indicate layers specific to Field 4)

* Group: New Group -> 'Field 4'

* Structure: Make sure that you select the same data structure as the Soil Survey layer, in our example 'SsurgoSoils'

Download Soils2.jpg



Click on Accept, as a result, a new layer with soils clipped in the selected field is created.

Use Selection tools -> Remove Selection, and turn off 'Soils' layer, to view only the Soils clipped in Field 4, as shown in the field below:

Download Soils3.jpg