gis and geologic mapping part 2 of 2 tools and methods to get started using gis as a base for...

GIS and Geologic MappingGIS and Geologic MappingPart 2 of 2Part 2 of 2

Tools and methods to get started using Tools and methods to get started using GIS as a base for geologic mapping GIS as a base for geologic mapping

USGS AstrogeologyUSGS Astrogeology

July 2006July 2006 GIS-based Mapping Part 2 (v.1)GIS-based Mapping Part 2 (v.1) 22

GIS-based MappingGIS-based Mapping

Though this presentation is geared toward Though this presentation is geared toward geologic mappers, the information is geologic mappers, the information is relevant to all GIS usersrelevant to all GIS users

Screen-shots are likely to differ from Screen-shots are likely to differ from individual viewsindividual views

GIS skills are developed through software GIS skills are developed through software interaction … be patient and try new things!interaction … be patient and try new things!

Tip icon will point out helpful hints throughout the presentationTip icon will point out helpful hints throughout the presentation


An important note.An important note. USGS Astrogeology primarily uses only one “brand” of GIS (ESRI’s USGS Astrogeology primarily uses only one “brand” of GIS (ESRI’s

ArcMap)ArcMap) Other brands exist, both free and commercialOther brands exist, both free and commercial ““Free”Free”

– Quantum GIS Quantum GIS (qgis.org/)(qgis.org/)– UDIG UDIG (udig.refractions.net/confluence/display/UDIG/Home)(udig.refractions.net/confluence/display/UDIG/Home)– Open EV Open EV (openev.sourceforge.net/)(openev.sourceforge.net/)– JUMP JUMP (jump-project.org/)(jump-project.org/)– GRASS GRASS (grass.itc.it/)(grass.itc.it/)

CommercialCommercial– TNTmips TNTmips (www.microimages.com/)(www.microimages.com/) – ER Mapper ER Mapper (www.ermapper.com)(www.ermapper.com)– PCI GeoMatica PCI GeoMatica (www.pcigeomatics.com(www.pcigeomatics.com))– Global Mapper Global Mapper (www.globalmapper.com)(www.globalmapper.com)– Integraph Integraph (www.intergraph.com)(www.intergraph.com)


GIS Support NodesGIS Support Nodes

ESRI online portal to technical informationESRI online portal to technical information– http://support.esri.comhttp://support.esri.com

ESRI ArcScriptsESRI ArcScripts– http://arcscripts.esri.com/http://arcscripts.esri.com/

ESRI Educational ServicesESRI Educational Services– Instructor-led trainingInstructor-led training– Virtual Campus coursesVirtual Campus courses– Web workshopsWeb workshops


GIS Support NodesGIS Support Nodes

Planet-specific information Planet-specific information ((e.g.e.g., data, discussion, , data, discussion, tutorials)tutorials)

– http://webgis.wr.usgs.gov/http://webgis.wr.usgs.gov/

USGS discussion board (login required)USGS discussion board (login required)– http://isis.astrogeology.usgs.gov/IsisSupport/http://isis.astrogeology.usgs.gov/IsisSupport/

index.php?c=9index.php?c=9

“Plugging keywords into a internet search engine is a great way to search for GIS-related assistance!”


Part 1 ReviewPart 1 Review

Introduced ArcMap & ArcCatalog interfacesIntroduced ArcMap & ArcCatalog interfaces Created a geodatabase (GDB)Created a geodatabase (GDB) Added project-specific Added project-specific attribute domainsattribute domains Built a Feature Dataset and added three Built a Feature Dataset and added three

Features (contacts, structures, units)Features (contacts, structures, units) Imported map bases (raster data)Imported map bases (raster data) Edited the Features by adding lines and Edited the Features by adding lines and

points (vector data)points (vector data)


Cleaning dataCleaning data Exploring ArcToolboxExploring ArcToolbox Building polygonsBuilding polygons Querying dataQuerying data Calculating spatial statisticsCalculating spatial statistics

Part 2 IntroductionPart 2 Introduction

“ESRI has on-line tutorials that are helpful in exploring the utility of ArcGIS. Go to www.esri.com and click on the “Training” tab.

http://www.esri.com/


Cleaning data - Cleaning data -

Cleaning digitized data means improving the Cleaning digitized data means improving the appearance of the data by correcting appearance of the data by correcting overshoots and undershoots, closing overshoots and undershoots, closing polygons, performing coordinate editing, etc. polygons, performing coordinate editing, etc. - paraphrased from - paraphrased from ESRI’s online GIS dictionaryESRI’s online GIS dictionary

“Taking time to clean your data as you digitize will help alleviate editing problems and spending excess time near the end of your project.”


Finish contact linework

Exercise continued from previous presentation…..


Notice that some lines are not connected. To ensure polygons are properly created,all lines must be CLOSED. We need to allow the feature to “snap” to other features.


Snapping tolerance is the Snapping tolerance is the distance at which vertices will distance at which vertices will connect automaticallyconnect automatically

Use drop-down to specify unit Use drop-down to specify unit of measurementof measurement

Tolerances are typically Tolerances are typically project- and scale-specificproject- and scale-specific

““Sticky move tolerance” will Sticky move tolerance” will allow your pointer to snap to allow your pointer to snap to applicable verticesapplicable vertices

“The editing options dialog box has several changeable parameters such as stream tolerance (the distance between vertices while streaming lines). Try some variations to see what happens!”


1. Select line to close with “select tool”

2. Choose “Modify Feature”from ArcEditor Task list


Use the mouse and snap ends together

Snap all lines together in the feature that is being edited. It is easiest to “zoom in”to see where features are not closed.

“A topology is a set of rules that constrains how vector data is arranged. Topologies can be used to identify where polyline features are not clean. Use Arc Help for more detail on building and verifying topologies”


Exploring ArcToolboxExploring ArcToolbox

ArcToolbox is an object in ArcMap and ArcToolbox is an object in ArcMap and ArcCatalog that contains sets of processing ArcCatalog that contains sets of processing tools. Is is presented as a “tree” of tools tools. Is is presented as a “tree” of tools grouped by functionality.grouped by functionality.

The toolbox function can be turned on in The toolbox function can be turned on in ArcMap and/or ArcCatalog by clicking on ArcMap and/or ArcCatalog by clicking on the general menu. the general menu.

“Hovering over menu buttons will provide a short description of the function the button will start”


ArcToolbox button in ArcMap


Toolbox window. Close byClicking the ‘x’


Toolbox windowToolbox window

Tools in the toolbox are Tools in the toolbox are grouped by similar functionsgrouped by similar functions

You can navigate through You can navigate through the tree to see what each the tree to see what each doesdoes

Toolboxes can be adapted Toolboxes can be adapted and populated with favorite and populated with favorite tools or built for specific tools or built for specific projectsprojects


Toolbox windowToolbox window

For example, to add a field For example, to add a field to an existing feature, to an existing feature, navigate to the “Add Field” navigate to the “Add Field” tooltool

Double-clicking will open Double-clicking will open the tool and provide the tool and provide additional information additional information (see (see next slide)next slide)


“The “Show/Hide Help” button at the bottom of the tool window will provide helpful information about the tool, required inputs, and options. Explore the toolbox by opening several tools and seeing what they do”


Building PolygonsBuilding Polygons

Using the toolbox, we can build polygons Using the toolbox, we can build polygons from our cleaned “contact” polyline featurefrom our cleaned “contact” polyline feature

Polygons are spatial features that have both Polygons are spatial features that have both areaarea and and perimeterperimeter

Polygons could represent regions, geologic Polygons could represent regions, geologic units, quadrangles, to name a fewunits, quadrangles, to name a few

Polygons can be built from Polygons can be built from closedclosed lines lines

“One method of geologic mapping is to build polygons from lines. However, lines can be built from polygons. In such a scenario, polygons are built first, perhaps using the Auto-Complete Polygon editing task. Check it out!”


Find necessary toolFind necessary tool

There are >400 tools!!! How do There are >400 tools!!! How do you know where to find the one you know where to find the one you need?!?!you need?!?!

Use the “Search” tab and type Use the “Search” tab and type in some keywordsin some keywords

To find the tool to build To find the tool to build polygons, we can type in polygons, we can type in “polygon” and click “Search”“polygon” and click “Search”

The “Locate” button will show The “Locate” button will show you where the tool resides on you where the tool resides on the directory treethe directory tree 3. Locate the tool

1. Enter keywords

2. “Click!”


Find necessary toolFind necessary tool

A toolbox search will yield A toolbox search will yield all keyword matchesall keyword matches

Open tools that you suspect Open tools that you suspect may be applicable and read may be applicable and read the function summarythe function summary

To build polygons, we will To build polygons, we will use the “Feature to use the “Feature to Polygon” toolPolygon” tool


Populate the dialog box with the necessary information. In our example, we will use“contacts” as the input feature . Notice that we can attribute our new polygons as they are being built by using the “units” point file.

“Note the location of the Show/Hide Help button.

It is your friend!”


After some brief computations, the tool process will finish and the newly-createdfeature will be added to the project.


Go into the polygon’s properties and change the symbology to use all the populated values for ‘TYPE’.


Querying the dataQuerying the data

GIS empowers the user to perform spatial GIS empowers the user to perform spatial searches across any or all data within a searches across any or all data within a projectproject

A “query” is A “query” is “a request to select features or “a request to select features or records from a database or feature”records from a database or feature”

The query expression is typically Boolean The query expression is typically Boolean (based on yes or no answers)(based on yes or no answers)

Queries are commonly performed using a Queries are commonly performed using a dialog box in ArcMapdialog box in ArcMap


Let’s say that the user wants to find all units that are labeled “plains material”. The user will need to query the data as follows.


Selecting by Selecting by feature attributesfeature attributes

Select the layer and Select the layer and field that the query field that the query will be based onwill be based on

““Get Unique Values” Get Unique Values” will give all values in will give all values in that fieldthat field

Build the query and Build the query and click “OK”click “OK”


Selecting by Selecting by feature locationfeature location

Features can be Features can be selected based on selected based on relationships with relationships with other featuresother features

Examine the “Select Examine the “Select by Location” window by Location” window for specificsfor specifics


Calculating Spatial StatisticsCalculating Spatial Statistics

A powerful tool to calculate statistics of a zone A powerful tool to calculate statistics of a zone dataset dataset (e.g., geologic units)(e.g., geologic units) based on values from based on values from a raster dataset a raster dataset (e.g., elevation)(e.g., elevation)

Spatial AnalystSpatial Analyst– Cell statisticsCell statistics– Neighborhood statisticsNeighborhood statistics– Zonal statisticsZonal statistics

Operates out of Spatial AnalystOperates out of Spatial Analyst– Right click empty space on tool bar and select “Spatial Right click empty space on tool bar and select “Spatial

Analyst”Analyst”


Cell StatisticsCell Statistics

““A function that calculates a statistic for each cell A function that calculates a statistic for each cell of an output raster that is based on the values of of an output raster that is based on the values of each cell in the same location of multiple input each cell in the same location of multiple input rasters.”rasters.” - paraphrased from ESRI’s online GIS dictionary - paraphrased from ESRI’s online GIS dictionary

For example, the user could find the range and For example, the user could find the range and maximum value of albedo from multiple maximum value of albedo from multiple overlapping images acquired in different seasonsoverlapping images acquired in different seasons

“Spatial Analyst tools such as cell statistics provide critical analytical components for the interpretation of raster and vector data. Statistics can help improve the quality of geologic maps.”


1. Add and/or Remove the raster layers that are required for the 1. Add and/or Remove the raster layers that are required for the statisticsstatistics

2. Set the statistic that is required (can be minimum, maximum, range, 2. Set the statistic that is required (can be minimum, maximum, range, sum, mean, std dev, variety, majority, minority, median)sum, mean, std dev, variety, majority, minority, median)

3. Type in the output raster name, either as a temporary file (default - 3. Type in the output raster name, either as a temporary file (default - will be erased the next time the project is closed) or as a TIFF, IMG, or will be erased the next time the project is closed) or as a TIFF, IMG, or Arc GRID.Arc GRID.

1

2

3


Neighborhood StatisticsNeighborhood Statistics

A function that calculates a statistic on a raster using a user-A function that calculates a statistic on a raster using a user-specified “neighborhood”, which implies an extent from specified “neighborhood”, which implies an extent from individual cells. The extent can be a annulus, circle, individual cells. The extent can be a annulus, circle, rectangle, or wedge.rectangle, or wedge.

The user specifies statistics type, neighborhood extent The user specifies statistics type, neighborhood extent (e.g., (e.g., circle with a radius of 4 km), circle with a radius of 4 km), and out output cell size and out output cell size (default-input cell size)(default-input cell size)

For example, the user could find the range and maximum For example, the user could find the range and maximum value of albedo from multiple overlapping images acquired value of albedo from multiple overlapping images acquired in different seasonsin different seasons

“Using Neighborhood Statistics, a user could create a range of filter types. For example, a median high pass filter can be produced by using a median neighborhood statistic and then subtracting the raster value.”


1. Determine the input dataset and field that will be the basis of the stats1. Determine the input dataset and field that will be the basis of the stats 2. Set the statistic (minimum, maximum, range, sum, mean, std dev, 2. Set the statistic (minimum, maximum, range, sum, mean, std dev,

variety, majority, minority, median) and the neighborhood (annulus, variety, majority, minority, median) and the neighborhood (annulus, circle, rectangle, wedge)circle, rectangle, wedge)

3. Set the neighborhood size3. Set the neighborhood size Set the output cell size, raster name, and locationSet the output cell size, raster name, and location

1

2

3

4


Zonal StatisticsZonal Statistics

A function that summarizes values in a raster A function that summarizes values in a raster within the zones of another layerwithin the zones of another layer

The user specifies the “zone dataset” (e.g., The user specifies the “zone dataset” (e.g., geologic units) the value raster dataset (e.g., geologic units) the value raster dataset (e.g., slope)slope)

Output is a Table that summarizes zone statisticsOutput is a Table that summarizes zone statistics For example, the user could find the range and For example, the user could find the range and

mean value of slope for geologic unitsmean value of slope for geologic units

“The Zonal Statistics function allows the user to produce a simplified graph of the statistics. Note the check box in the dialog box.”


1. Set the Zone dataset (the feature that contains the region upon 1. Set the Zone dataset (the feature that contains the region upon which statistics need to be created)which statistics need to be created)

2. Set the Value raster (the raster dataset that will be the base of the 2. Set the Value raster (the raster dataset that will be the base of the statistics)statistics)

3. Set the statistic that is required (can be minimum, maximum, range, 3. Set the statistic that is required (can be minimum, maximum, range, sum, mean, std dev, variety, majority, minority, median)sum, mean, std dev, variety, majority, minority, median)

1

2

3


Cleaning data is an important aspect of digitizing Cleaning data is an important aspect of digitizing vector datavector data

Cleaning can consist of closing gaps, smoothing, Cleaning can consist of closing gaps, smoothing, removing overshoots (dangles), and verifying removing overshoots (dangles), and verifying projectionsprojections

ArcToolbox is a suite of tools that is accessible ArcToolbox is a suite of tools that is accessible through ArcMap and/or ArcCatalogthrough ArcMap and/or ArcCatalog

ArcToolbox provides a hierarchal tree structure of ArcToolbox provides a hierarchal tree structure of tools that are grouped by functionalitytools that are grouped by functionality

ArcToolbox can be searched using keywordsArcToolbox can be searched using keywords

SummarySummary


Tools have a “show details” button in the dialog Tools have a “show details” button in the dialog box that provide important details about the tools box that provide important details about the tools functionalityfunctionality

There are several stylistic and logistic approaches There are several stylistic and logistic approaches to building polygonsto building polygons

Polygons can be created from cleaned linework Polygons can be created from cleaned linework (e.g., build geologic units from geologic contacts)(e.g., build geologic units from geologic contacts)

A point file can be used to attribute newly-created A point file can be used to attribute newly-created polygon featurespolygon features

Summary, Summary, cont’dcont’d


User’s can query their data using either User’s can query their data using either feature attributes or feature locationsfeature attributes or feature locations

Queries are excellent ways to single out Queries are excellent ways to single out pertinent datapertinent data

Specialized statistics are provided through Specialized statistics are provided through the Spatial Analyst extensionthe Spatial Analyst extension

Spatial statistics can include cell statistics, Spatial statistics can include cell statistics, neighborhood statistics, and zonal statisticsneighborhood statistics, and zonal statistics

Summary, Summary, cont’dcont’d

gis and geologic mapping part 2 of 2 tools and methods to get started using gis as a base for...

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