The SSURGO soils survey is a very useful tool for people in need of soils information. However, the SSURGO soils database is too large and complex for practical use in a geographic information system (GIS). A simplified version of the database was developed and combined with an array of other landscape data to make county based GIS products that are utilized by both portable computer and web-based applications. This allows for wider distribution of the soils information and the ability to take the data to the field

Langille, James

Lynn-Patterson, Kris

O\u27Geen, Anthony T

Schmierer, Jerry L

English

Clemson University: TigerPrints

The Journal of Extension Volume 45 Number 4 Article 30 8-1-2007 Converting a SSURGO Soils Database into a Simple Soils Database for Use in Portable Computer and Web-Based GIS Applications Jerry L. Schmierer University of California Davis, jlschmierer@ucdavis.edu Kris Lynn-Patterson Kearney Agricultural Center, krislynn@uckac.edu James Langille Kearney Agricultural Center, jamesl@uckac.edu Anthony T. O'Geen University of California Davis, atogeen@ucdavis.edu This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License. Recommended Citation Schmierer, J. L., Lynn-Patterson, K., Langille, J., & O'Geen, A. T. (2007). Converting a SSURGO Soils Database into a Simple Soils Database for Use in Portable Computer and Web-Based GIS Applications. The Journal of Extension, 45(4), Article 30. https://tigerprints.clemson.edu/joe/vol45/iss4/30 This Tools of the Trade is brought to you for free and open access by the Conferences at TigerPrints. It has been accepted for inclusion in The Journal of Extension by an authorized editor of TigerPrints. For more information, please contact kokeefe@clemson.edu. 	 JOEHOME JOURNAL GUIDELINES ABOUT	JOE CONTACT NATIONAL	JOB	BANKCurrent	Issues Back	IssuesAugust	2007	//	Volume	45	//	Number	4	//	Tools	of	the	Trade	//	4TOT7Converting	a	SSURGO	Soils	Database	into	a	Simple	SoilsDatabase	for	Use	in	Portable	Computer	and	Web-Based	GISApplicationsAbstractThe	SSURGO	soils	survey	is	a	very	useful	tool	for	people	in	need	of	soils	information.	However,the	SSURGO	soils	database	is	too	large	and	complex	for	practical	use	in	a	geographicinformation	system	(GIS).	A	simplified	version	of	the	database	was	developed	and	combinedwith	an	array	of	other	landscape	data	to	make	county	based	GIS	products	that	are	utilized	byboth	portable	computer	and	web-based	applications.	This	allows	for	wider	distribution	of	thesoils	information	and	the	ability	to	take	the	data	to	the	field.	IntroductionThe	SSURGO	soils	database	developed	by	the	USDA	Natural	Resource	Conservation	Service	(NRCS)has	a	wealth	of	information	that	has	been	used	extensively	since	the	first	paper	soil	survey	bookswere	printed.	With	the	development	of	the	digital	information	format,	many	county	soil	surveymaps	have	been	converted	to	digital	shape	files	that	can	be	used	by	computer	driven	geographicinformation	systems	(GIS).	The	many	tables	of	data	that	are	related	to	the	soils	maps	have	beenplaced	into	a	complex	database.The	NRCS	has	provided	this	information	to	the	public	in	a	compact	disk	(CD)	format	and	is	alsoavailable	via	the	Internet	at	the	NRCS	Soil	Web	Survey	site.	The	CD	is	basically	a	digital	form	of	thecounty	soil	survey	books	with	printable	pages.	The	NRCS	Soil	Web	Survey	site	is	a	searchable	Website	for	delivering	all	the	data	in	the	SSURGO	soils	database	but	has	no	capability	of	interactingwith	a	GIS.Jerry	L.	SchmiererAgronomy	Farm	AdvisorCooperative	ExtensionColusa,	Californiajlschmierer@ucdavis.eduKris	Lynn-PattersonGIS	Academic	CoordinatorKearney	Agricultural	CenterParlier,	Californiakrislynn@uckac.eduJames	LangilleGIS	Programmer/AnalystKearney	Agricultural	CenterParlier,	Californiajamesl@uckac.eduAnthony	T.	O'Geen	Cooperative	Extension	Soil	Resource	SpecialistSoils	&	Biogeochemistry	ProgramDavis,	Californiaatogeen@ucdavis.eduUniversity	of	CaliforniaTo	provide	the	SSURGO	data	to	GIS	users,	NRCS	has	made	the	county	databases	and	related	shapefiles	available	through	the	Soils	Data	Mart	Web	site.	In	order	to	retrieve	the	database	information,a	Microsoft	Access	soils	database	and	the	spatial	and	tabular	files	specific	for	each	county	must	bedownloaded	to	a	local	computer	and	decompressed.	Then	a	data	loading	program	must	be	run	toassociate	these	files	to	the	database.	The	result	is	a	county-specific	database	that	ranges	from	200to	300	megabytes	in	size	with	over	130	tables.These	tables	are	woven	together	in	a	very	complex	web	of	relationships.	Figure	1	partiallyillustrates	this	complex	system	of	tables	and	relationships.	This	database	provides	all	of	thedocumentation	for	the	soil	survey	and	contains	information	in	pre-formatted	reports.	It	containsinformation	for	a	wide	variety	of	users,	thus	making	it	difficult	to	extract	only	specific	information.It	suffers	the	plight	of	"too	much	information."	The	problem	with	using	the	SSURGO	database	in	aGIS	is	that	it	was	designed	as	a	one-size-fits-all.	It	is	too	big,	complex	and	cumbersome	and	doesnot	fit	the	portable	or	web-based	GIS	venues.Figure	1.Table	Relationships	from	Original	SSURGO	Database	Showing	Only	Some	of	the	Tables	and	theComplex	Relationships	Between	Tables	Key	Tables	and	RelationshipsOur	approach	to	this	problem	was	to	simplify	the	database	to	the	fewest	possible	tables	with	onlythe	pertinent	information	for	our	purpose.	This	resulted	in	reducing	the	size	of	the	database	to	amanageable	level,	15	to	30	megabytes	as	compared	to	the	original	database	at	ten	times	the	size.To	do	this,	we	prioritized	the	information	that	we	wanted	to	retrieve	and	studied	the	schema(framework	of	the	database)	in	order	to	understand	the	relationships	between	the	tables.	Only	fourtables	were	chosen	to	include	in	our	abbreviated	database	as	these	tables	contained	the	majorityof	the	information	that	we	needed.	Figure	2	displays	these	four	tables	and	the	simple	relationshipsbetween	these	tables.Figure	2.Extracted	Tables	and	Relationships	in	the	Simplified	Database	Showing	the	Four	Tables	The	mapunit	and	muaggat	tables	contain	the	soil	series	information	and	have	a	1	to	1	relationship,meaning	the	data	in	the	two	tables	can	be	combined.	There	are	one	to	many	relationshipsbetween	mapunit	to	component	tables	and	component	to	chorizon	tables.	This	simply	means	thatthere	can	be	many	soil	components	to	a	soil	series	and	that	there	can	be	many	soil	horizons	to	asingle	soil	component.	These	relationships	allow	a	GIS	to	drill	down	into	the	data	to	retrieveinformation	about	a	specific	location.Building	the	New	DatabaseThe	spatial	shape	files	included	in	the	database	are	usable	directly	by	the	user's	GIS	but	can	onlybe	joined	to	a	single	table,	and	there	are	four	tables	of	information	needed.	Using	the	ESRI	GISprograms	ArcInfo	or	ArcEditor,	the	selected	tables	were	imported	into	a	personal	geodatabase,	andthe	relationships	built	between	the	tables.	ArcMap	was	used	to	join	the	map	shape	file	to	the	soilsseries	table	(mapunit)	and	create	a	relationship	class	for	the	other	tables.	The	result	of	this	effort	isvisible	when	the	GIS	identify	tool	is	used	to	display	table	attribute	data;	the	multiple	layers	of	thegeodatabase	are	displayed	(called	drilling	down	through	the	data).	Examples	of	this	drill	downcapability	are	shown	in	Figures	3	and	4.Specific	table	attribute	(column)	data	can	be	re-named,	calculated,	or	changed	by	exporting	atable	to	a	Microsoft	Excel	spreadsheet	for	manipulation,	then	importing	it	back	into	the	database.In	our	case,	we	combined	the	mapunit	and	muaggat	tables	into	a	single	table.	We	also	convertedsome	of	the	attribute	values	from	centimeters	to	inches	because	that	would	be	more	easilyunderstood	by	the	people	using	the	GIS.Figure	3.View	of	Map	and	Soils	Layer	Drill	Down	from	Web-Based	GIS	Figure	3.Detail	View	of	Soils	Layer	Drill	Down	Showing	Soil	Series,	Component,	and	the	Top	Horizon	LayerInformation	Using	the	New	DatabaseWe	built	these	simplified	soils	databases	for	the	17	Central	Valley	counties	of	California	anddeveloped	a	GIS	for	each	county.	Many	map	layers	were	included:	soils	data,	land	use,	waterdistricts,	political	boundaries,	roads,	waterways,	township,	range,	and	section	information	alongwith	historic	topography	maps	and	aerial	imagery.	Data	sets	were	packaged	on	DVDs	because	ofthe	large	amount	of	data,	in	excess	of	one	gigabyte	per	county.	Tutorials	and	online	help	are	alsoprovided	on	the	DVDs.	These	data	sets	allow	users	of	ArcGIS	or	the	free	downloadable	programArcReader	to	use	the	GIS	on	a	portable	computer	for	field	use.	This	is	a	powerful	feature	of	thisproject,	especially	when	the	portable	computer	is	equipped	with	a	GPS	device.In	order	to	reach	a	wider	general	population	audience,	who	do	not	have	GIS	software	or	thetraining	to	use	it,	we	developed	a	Web-based	GIS	that	a	user	only	needs	an	Internet	connectionand	browser	to	use.	Our	Web-based	GIS	that	incorporates	the	simple	SSURGO	database	can	beviewed	at	<http://arcims.gis.uckac.edu/SoilsToGo>.ReferencesSoil	Survey	Staff,	Natural	Resources	Conservation	Service,	United	States	Department	ofAgriculture.	(2005).	Soil	survey	geographic	(SSURGO)	database	for	California.	Available	at:http://soildatamart.nrcs.usda.govSoil	Survey	Staff,	Natural	Resources	Conservation	Service,	United	States	Department	ofAgriculture.	(2006)	NCSS	soil	Web	survey.	Available	at:	http://websoilsurvey.nrcs.usda.gov/app/Copyright	�	by	Extension	Journal,	Inc.	ISSN	1077-5315.	Articles	appearing	in	the	Journal	become	the	property	of	theJournal.	 Single	 copies	 of	 articles	may	 be	 reproduced	 in	 electronic	 or	 print	 form	 for	 use	 in	 educational	 or	 trainingactivities.	Inclusion	of	articles	in	other	publications,	electronic	sources,	or	systematic	large-scale	distribution	may	bedone	only	with	prior	electronic	or	written	permission	of	the	Journal	Editorial	Office,	joe-ed@joe.org.If	you	have	difficulties	viewing	or	printing	this	page,	please	contact	JOE	Technical	Support©	Copyright	by	Extension	Journal,	Inc.	ISSN	1077-5315.	Copyright	Policy

Converting a SSURGO Soils Database into a Simple Soils Database for Use in Portable Computer and Web-Based GIS Applications

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Converting a SSURGO Soils Database into a Simple Soils Database for Use in Portable Computer and Web-Based GIS Applications

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