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I'm trying to isolate a couple specific soil types from the GIS soils layers for a county in my state in the US.

I downloaded the data: ftp://ftp.igsb.uiowa.edu/gis_library/Counties/Adair/soil_01/soils_01.zip

And loaded the .shp file as a vector layer. I can see all the shapes of different soil types but can't figure out how to isolate and display just a couple of them.

Can anyone help with this problem?

  • which ones do you want to isolate and display? – ed.hank Feb 23 '16 at 23:56
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To isolate and work with only a certain soil type you want to open your attribute table (right click on the layer in the layers panel and and open the attribute table)

Then use the select by expression button: see pic below

enter image description here

You will want to use the expression

"SOILNAME" LIKE '%SHELBY%' to select all soils with the name SHELBY in the field of SOILNAME

If you wanted to select all records with SHELBY in the SOILNAME field and with a value of 1 in the SOILS_01_ field (assuming that is an INT field and not a text field) you would use:

"SOILNAME" LIKE '%SHELBY%' AND "SOILS_01_" = 1

Once you have selected your records, go back out to the Layers Properties (where you opened the attribute table) and select save layer as. Choose options similar to the ones below:

enter image description here

You want to save only selected features, and then load that layer onto the map. Once you have done that you will have a result like mine below (my result I used a Select by Expression of "PTMAT_DESC" LIKE '%Loess%' to show me only records where the field PTMAT_DESC has a value of anything containing the characters Loess . The final result is shown below.

enter image description here

Once you have that data you can use what Whyzar mentions to improve your symbology and how you are visualizing your data.

Here is a good tutorial on select by expression:

http://maps.cga.harvard.edu/qgis/wkshop/query.php

QGIS Select by Expression

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  • Those steps worked! I'm looking for just the sandy soils - which are not common here in Iowa. Been struggling with this for quiet a while. Really appreciate the help. – Thamnophis Feb 24 '16 at 3:56
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There are several ways you may attempt to style your GIS data in QGIS. Here is a tutorial which I believe is a good resource in styling your soils GIS data.

Here are same snapshots of the step involved and their results

enter image description here

enter image description here

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