Data Set ID:

SMAPVEX12 Core-Based Soil Texture Data, Version 1

This data set contains in situ soil texture data collected with coring devices at several sites as part of the Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12).

This is the most recent version of these data.

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Data: Data integrity and usability verified

Documentation: Key metadata and user guide available

User Support: Assistance with data access and usage; guidance on use of data in tools

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Data Format(s):
  • ASCII Text
Spatial Coverage:
N: 49.96, 
S: 49.44, 
E: -97.85, 
W: -98.51
Spatial Resolution:
  • 3.2 km x 3.2 km
Temporal Coverage:
  • 7 June 2012 to 19 July 2012
Temporal Resolution1 dayMetadata XML:View Metadata Record
Data Contributor(s):Paul Bullock, Aaron Berg

Geographic Coverage

Other Access Options

Other Access Options


As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Bullock, P., A. Berg, and G. Wiseman. 2014. SMAPVEX12 Core-Based Soil Texture Data, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: [Date Accessed].
11 March 2020
Last modified: 
11 March 2020

Data Description

This data set contains in situ soil texture data collected with coring devices at several sites as part of the Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12).


Parameters in this data set include soil texture fractions and soil texture class. Specifically, the parameters are:

  • sand fraction
  • silt fraction
  • clay fraction
  • very fine sand fraction
  • fine sand fraction
  • medium sand fraction
  • coarse sand fraction
  • very coarse sand fraction
  • abbreviated texture name
  • texture name

All parameters (expect for the texture names) are expressed as percentages.

File Information

Format and File Contents

Data are provided in ASCII text files. 
SV12CST_Soil_Txt_Properties_ver4.txt contains the soil texture from ground sampling. 
Field_Sites_ver4_coords.txt contains the UTM coordinates for the sampling points.

Table 1 describes the data columns of the sampling data file, while Table 2 describes the columns of the geolocation file.

Table 1. Data Fields and Descriptions for SV12CST_Soil_Txt_Properties_ver4.txt
Column Heading Description
SV12CST Data Set Short Name
OBJECT_ID ID of the sample
Site_ID ID of the field and the sample point within the field
Sand Percentage of the total soil contained in the sand fraction
Silt Percentage of the total soil contained in the silt fraction
Clay Percentage of the total soil contained in the clay fraction
SF_Very_Fine Percentage of the total soil contained in the very fine sand fraction (<106 um)
SF_Fine Percentage of the total soil contained in the fine sand fraction (106-250 um)
SF_Medium Percentage of the total soil contained in the medium sand fraction (250-500 um)
SF_Coarse Percentage of the total soil contained in the coarse sand fraction (500 um-1 mm)
SF_Very_Coarse Percentage of the total soil contained in the very coarse sand fraction (>1 mm)
Texture_Abbrev Abbreviated soil texture name
Texture Soil texture name
Table 2. Data Fields and Descriptions for Field_Sites_ver4_coords.txt
Column Heading Description
OBJECTID ID of the data record
Site_ID ID of the field and the sample point within the field
X UTM X coordinate
Y UTM Y coordinate

Spatial Information


Southernmost Latitude: 49.44°N
Northernmost Latitude: 49.96°N
Westernmost Longitude: 98.51°W
Easternmost Longitude: 97.85°W


The spatial resolution was approximately 3.2 km. Sampling was performed on sites approximately one quarter section (0.8 km by 0.8 km) in size.


Data are provided in Universal Transverse Mercator (UTM), Zone 14 N, World Geodetic System 1984 (WGS84) coordinates.

Temporal Information

Coverage and Resolution

Measurements were taken one time for each field site within the study period from 07 June 2012 through 19 July 2012.

Software and Tools

No special tools are required to read these data. Any text editor or Web browser will display the ASCII text files.

Data Acquisition and Processing

Theory of Measurements

A particle size analysis of soil core samples was conducted to determine the textural class of the samples.

Processing Steps

During flight days, crews were instructed to collect one bulk density core per field (the primary reason for this was the calibration of the handheld sensors). The location of the one bulk density site was moved each flight day such that by the end of the campaign, one sample had been collected at each sampling location within each field. This strategy yielded more than 850 cores during the course of SMAPVEX12. The dimensions of the soil cores were approximately 4.6 cm in height and 4.7 cm in diameter with a core volume of 80 cm3. When the crew arrived at the designated bulk density site for that particular sampling day, they took their three standard probe readings. As well, the crew collected a soil core and three additional probe readings. These three additional readings were located in close proximity to the location of the soil core extraction, and were recorded separately on the field sheets. Crews were careful to collect an undisturbed soil sample. These samples (soil and core) were placed in a soil tin with a lid, with the tin then being placed in a re-sealable plastic bag to minimize moisture loss. Soil cores were transported back to Winnipeg for weighing and drying. The entire sample (soil, core, tin and bag) was weighed. The tin was then removed from the plastic bag and placed in a soil drying oven. The samples were oven dried for 24 hours at 105°C. Following drying, the entire sample (soil, core, tin) was then re-weighed. The particle size analysis was conducted using the dried samples.

See more details in Section 2.1.1 of the SMAPVEX12 Database Report, released 18 December 2012.

Error Sources

Representation error is assumed to be relatively small due to the fact that a core sample was analyzed from each soil moisture measurement location at each site. Refer to the Processing Steps section of this document.

Quality Assessment

The quality of the data corresponds to the quality of the soil texture analysis carried out in similar soil moisture field experiments.

References and Related Publications

McNairn, H., T. Jackson, G. Wiseman, S. Belair, A. Berg, P. Bullock, A. Colliander, M. Cosh, S. Kim, R. Magagi, M. Moghaddam, J. Adams, S. Homayouni, E. Ojo, T. Rowlandson, J. Shang, K. Goita, and M. Hosseini. 2013, In Review. The Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12): Pre-Launch Calibration and Validation of the SMAP Satellite. IEEE Trans. Geosci. Rem. Sens.


Grant Wiseman
Science and Technology Branch
Agriculture and Agri-Food Canada
200-303 Main Street
Winnipeg, Manitoba, R3C 3G7, Canada
phone: +1 204.259.4006

Paul Bullock
Department of Soil Science
University of Manitoba
13 Freedman Crescent
Winnipeg, Manitoba, R3T 2N2, Canada
phone: +1 204.474.8666

Aaron Berg
Department of Geography
University of Guelph
Guelph, Ontario, N1G 2W1, Canada
phone: +1 519.824.4120


Agriculture and Agri-Food Canada, National Aeronautics and Space Administration, U.S. Department of Agriculture, Environment Canada, U. Manitoba, U. Guelph, Massachusetts Institute of Technology, U. South Carolina, U. Colorado, U. Sherbrooke, Ohio State, U. Montana, Florida International U., U. Southern California, Texas A&M, Georgia Institute of Technology, U. Washington are acknowledged for their support for the campaign.

Field Sampling Team

Aaron Berg, University of Guelph
Alan Rich, University of Manitoba
Alicia Joseph, NASA GSFC
Alexandra Konings, MIT
Amine Merzouki, Agriculture and Agri-Food Canada
Bin Fang, U.S. Carolina
Brandon Wyryha, Agriculture and Agri-Food Canada
Brian Miller, University of Manitoba
Catherine Champagne, Agriculture and Agri-Food Canada
Craig Smith, Environment Canada
Christina Neva Rivera, Agriculture and Agri-Food Canada
Dominik Schneider, University of Colorado
Erika Podest, JPL
Erle Einarsson, Agriculture and Agri-Food Canada
Evan Rodgers, Agriculture and Agri-Food Canada
Grant Wiseman, Agriculture and Agri-Food Canada
Greg Gibbons, Agriculture and Agri-Food Canada
Heather McNairn, Agriculture and Agri-Food Canada
Hida Manns, University of Guelph
Hoda Jafarian, University of Sherbrooke
Jacqueline Freeman, Agriculture and Agri-Food Canada
Jeff Ouellette, Ohio State
Jennifer Watts, University of Montana
Jiali Shang, Agriculture and Agri-Food Canada
John Fitzmaurice, Agriculture and Agri-Food Canada
Jon Belanger, University of Guelph
Justin Adams, University of Guelph
Kalifa Goïta, University of Sherbrooke
Karel Janik, University of Sherbrooke
Kaighin McColl, MIT
Kurt Gottfried, Agriculture and Agri-Food Canada
Luis Perez, FIU – Florida International University
Marco Carrera, Environment Canada, Meteorological Research Division
Maria Abrahamowicz, Environment Canada
Mariko Burgin, University of Southern California
Maheshwari Neelman, Texas A&M
Matt Jones, University of Montana
Mehdi Hosseini, University of Sherbrooke
Mike Cosh, USDA, ARS Hydrology and Remote Sensing Laboratory
Mustafa Aksoy, Ohio State
Najib Djamai, University of Sherbrooke
Nandita Gaur, Texas A&M
Narendra Das, JPL
Parag Narvekar, MIT
Parinaz Rahimzadeh, University of Guelph
Patrick Rollin, Agriculture and Agri-Food Canada
Paul Bullock, University of Manitoba
Peggy O'Neill, NASA GSFC
Rachel Molloy, Agriculture and Agri-Food Canada
Rebecca Warren, University of Guelph
Rebecca Scriver, University of Guelph
Ramata Magagi, University of Sherbrooke
Robert Terwilleger, University of Florida
Rotimi Ojo, University of Manitoba
Ruzbeh Akbar, University of Southern California
Sab Kim, JPL
Sarah Banks, Agriculture and Agri-Food Canada
Sarah Dyck, Environment Canada
Saeid Homayouni, Agriculture and Agri-Food Canada
Shawna McKnight, Georgia Institute of Technology
Sonia Becenko, Agriculture and Agri-Food Canada
Stacie Westervelt, University of Manitoba
Steven Chan, JPL
Syed Anwar, Agriculture and Agri-Food Canada
Tien-Hoa Liao, University of Washington
Tracy Rowlandson, University of Guelph
Vanessa Escobar, NASA GSFC

Document Information


July 2014


March 2020

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