School of Geosciences

ArcGIS for Geoscientists

R. Armit & T. Carmichael

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GIS

A geographic information system (GIS) is a system designed to

capture, store, manipulate, analyze, manage, and present all types of

spatial data.

From tracking diseases to vectors to mineralisation.

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GIS

Iogas Gocad

The Package

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ArcMap

ArcScene

ArcGlobe

Online guide available at:

version 10.0 help

version 10.1 help

version 10.2 help

Modern light table

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Arcmap – Lithologies and samples in Armit et al. 2014 Mount Painter

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ArcScene – DTM of northern Flinders Ranges

ArcScene flyins

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ArcGlobe – 2.5 Million scale Australia Faults and Global seismicity for last 10 years.

ArcMap

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Practical data available at: http://users.monash.edu.au/~rjarmit/GIS/Project%20files.zip

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The interface

Major components of the Interface screen

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Table of contents

Data Frame

ArcCatalog

ArcToolbox

Identify features

Attributes

Attributes table

The blue arrows

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Table of contents

Data Frame ArcCatalog

Identify features

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ArcToolbox

Attributes

Attributes

table

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The blue

arrows

The dashboard

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Panning and zooming

Opening the arcCatalog, Toolbox or TOC windows

Drawing – not that same as editing (not spatially linked), however can convert

Measuring and identify features

Setting up your project

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• Define projection

• Add basemap

• Add data (different types)

• Georeference available images

You must make a choice of Datum and coordinate system for your project. Normally depends on scale and location of project.

Making an error here can put your 100 of metres out to half the

globe. Below is a brief summary of the Australian map grid systems.

Spheroid Datum Projection

WGS84 WGS84 World UTM (world)

AMG66 ANS70 AGD66 UTM (local using zones)

AMG84 ANS70 AGD84 UTM (local using zones)

MGA94 GRS80 AFN / GDA94 UTM (local using zones)

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Defining the projects projection

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Base maps

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Basemaps

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Imagery in ArcMap already geo-referenced

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Adding data

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• Types of data

• Raster

• Vector

• Table

Date Easting Northing Location Lithology Measurement Strike Dip Dir Dip_Dir

26/05/

2009 660024 5860610

Mt

Moornambool

East Face

Pelitic

Schist S0 161 20 W 251

26/05/

2009 660024 5860610

Mt

Moornambool

East Face

Pelitic

Schist S1 20 42 W 110

26/05/

2009 660024 5860610

Mt

Moornambool

East Face

Pelitic

Schist S2 161 20 W 251

26/05/

2009 660024 5860610

Mt

Moornambool

East Face

Pelitic

Schist S4 190 50 E 100

26/05/

2009 660730 5860636

Mt

Moornambool

East Face

Pelitic

Schist S2 128 88 W 218

26/05/

2009 660087 5860668

Mt

Moornambool

East Face

Pelitic

Schist S0 160 50 W 250

26/05/

2009 660087 5860668

Mt

Moornambool

East Face

Pelitic

Schist F2 30 214 30

26/05/

2009 660087 5860668

Mt

Moornambool

East Face

Pelitic

Schist F3 40 220 40

26/05/

2009 660087 5860668

Mt

Moornambool

East Face

Pelitic

Schist S1 2 36 W 92

26/05/

2009 660087 5860668

Mt

Moornambool

East Face

Pelitic

Schist S2 176 32 W 266

Raster

Vector

Table

Adding data – many ways

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Dragging the file in.

More complicated in Windows Ex with multiple file extensions

Rasters

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Common file extensions include:

Tiffs, jps, png, gif, img

Multi files like .hdr, .bil (band interleaved)

Plug in required formats include geosoft .grd format

Geotiffs and georeferenced tagged jpegs supported and easy to use

Raster types in ArcMap 10

However as general rule: Raster that you require that colour values to remain

Fixed are best imported as jpg, tiff or png.

Gridded raster files such as grd, bil, ers will require colour ramp processing on

Import.

If the raster is georeferenced then it will often have a number of extra files that

You will need to copy across to keep geo referencing info (e.g. .aux. rrd).

These are not visible through “add data” or arcCatalog.

One way to reduce file size is to keep rasters as raster database .gdb

Building pyramids and display types

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Nearest neighbour for rasters with text etc.

Bilinear for gridded data eg. Geochem or geophysics

Transparency

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In the same window you can change

The transparency of the layer.

This is useful to visualise or merge two or

more images.

Georeferencing rasters

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On published maps, the projection

and grid values are normally provided

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Georeferencing rasters

Control points

Vector

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A vector is a dataset which is

composed of points, lines and

polygons, rather then individual

pixels.

By clicking Add data from the

standard ribbon and navigating to a

file, you can open a wide array of

files.

Geodatabase – pros and cons

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A geodatabase is a way to store a variety of different types of spatial data in

the one location.

You can also set an array of different rules and relationships between all your

data.

Depending on how deep into GIS that

you are getting, a Geodatabase could be

too involved as it is very time

consuming.

It also decreases the amount of

interoperability (if you’re dragging files

between different programs)

Topology

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Topology, in terms of GIS refers to a set of rules and behaviours that model

how points, lines and polygons relate to each other.

When creating features in GIS, either topological or discrete rules can be used

to define these features.

In the following examples we will use discrete rules to create each of the

different feature classes (e.g. points, lines and polygons)

Creating a point layer

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Creating a point layer

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Creating a point layer

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• Digitizing polylines is done in the same way that

the creation of points, except that the end result is

defined by a line, instead of a single point.

• The can be used to represent a

large amount of geological data

that is defined as linear.

• It is extremely important to use

the style tool to make sure that

you can visualise what each of

your line represents.

• This will be covered later in this

course.

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• Layers that are created as Polygons are initially

added in the same way that polylines and points are.

• Polygons are used to define enclosed 2D areas. It is

defined by a set of (x,y) co-ordinate pairs.

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• Create an initial polygon by selecting

points on the map similarly to placing

points or polylines, the program will join

these points with straight lines.

• By using the Snapping Options from

the Snapping menu, you can snap to

another feature.

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• The data you initially collect in the field will unlikely be in a format that you can

directly import into a GIS package.

• The easiest way to solve this is to convert a table (usually a .csv file) into

something more workable.

Using GIS it is possible to turn field data, into manipulable, useful, information 43

• It is vital that before you go out into the field, that you know what data you’re

going to collect and how your input table should be set up.

• What information do you need to record at each location?

• Do you have a comments section to record pertinent information?

• What coordinate system is my GPS in?

• Was my data input into my table correctly? (Have I qaqc’d my data?)

• Are all my measurements in Strike and dip or dip and dip direction?

• Do my numbers make sense?

• Did I record them all in the same way?

• All of these questions (and more!) need to be dealt with before you try to

import your data.

• Otherwise, any errors that you bring in will be involved in your interpretation.

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Symbol rotation, level and the lyr file

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Symbol rotation, level and the lyr file

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Join and relate tables

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define the join based either on attributes, a

predefined geodatabase relationship class

or by location (also referred to as a spatial

join).

Queries

Spatially related

Attribute related

Combined queries

Quick queries

Exporting and subsampling from the query

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• There are several important features of the

query builder which can make your life

infinitely easier.

• If you select an option from the Fields sub-

menu and then hit sample (or all) you get the

values that are present in that field.

• By using the Operators we can build a query

which will highlight certain things.

• If we’re working with text then its easiest to choose a value from the Values

because it needs to be exact.

• The IF and AND functions can help highlight areas which have more then one

characteristic that we’re interested in.

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• By creating this query we

can highlight only the

features which are

Silurian(Ludlow) and are

Intrusives.

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http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//00s50000002t000000

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Field calculator and calculating

geometries

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Length, volume, area, azimuth, centroids and many more maths can be easily

calculated.

Open an attributes table

(right mouse click a layer in

TOC) and click attributes

table.

Click on a column heading

or field. Click ‘field

calculator’ or ‘calculate

geometry’

Calculate Geometry

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Allows simple area, length, centroid calculations depending on the data type.

Field calculator

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Allows for simple mathematical calculations to be made on the data (statistics a level up).

If you need to more complex inter related calculations then use the ArcToolbox instead.

The layout window and map production

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• Layout view

• Bookmarks

• 2nd zoom controls

• 2nd data frame

• Renaming for

legend

• Grids

• Legend

• North Arrow

• Placement

• Clipping entire

data

• Merged rasters

• Export types

• Issues with

linework etc.

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The layout

window

Two zoom controls – one for frame and

one for data extent

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Bookmarks

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Use this to define a fixed zoom area so if you need to keep looking at more

detail and back out you keep the same extent for your output map. Massive

time saver. Otherwise use blue arrows to go back a forth extents.

Insert legend, North Arrow, scale bar

Insert a second data frame – Very good and automated frame extent on larger data sets e.g.

for study location on country map etc.

Legend

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• Use the L and R arrows to add which selected

items you wish to add to the Legend and how many

columns you want.

• Up and Down control the order for the legend.

• The rest of the legend wizard is stylistic options and

this is up to you.

• You can also add labels for features from the

‘labels’ tab in the properties of each layer.

• You can edit the legend, north arrow and scale

after you have added them to the layout. Make sure

you can selected the item you want to amend (blue

corner nodes appear). Then right mouse click and

go to the properties. Change the style, scale, fonts,

columns etc. will it works with your output.

Adding grids, scale and north arrow

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• To add a coordinate system to your output, right

click the main data frame. Click ‘properties’.

• Click on ‘Grids’ tab. Click ‘new Grid’.

• Choice either graticules for lats and longs or

measured grid for UTM units.

• Choice if you want grid lines, ticks or blank and the

interval.

• You will then have a correctly scaled grid for your

image.

• The same can be done for a secondary data frame.

• Add a scale bar from the same insert menu.

• Click ‘properties’. Remove the division before 0 and

if in the UK or Australia and using Kilometres, edit

the label box to spell this ‘correctly’.

• Number of divisions depends on how detailed you

need the scale.

• You can add a north arrow using the same menu

and its pretty straight forward. Resize by dragging

the blue corner nodes once on the layout page.

Secondary data frame

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• Either drag items down into the new frame or add them as

you would for the primary frame.

• If you want to show the extent of one frame on other.

Select the frame you want to show it on.

• Click on ‘extent Indicators’ tab

• Click the arrow to move the data frame to the right hand

column for it to show in extent.

• Click ‘Frame’ to choose the thickness of the outline etc.

This extent will change as you move in or out and will

always represent a geographically correct extent.

Exporting – many options

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Post GIS image processing

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You can edit your images in Adobe illustrator fro ArcMap by saving as an .ai.

Remember to click update on opening the file in adobe for fonts as these

vary and will not show otherwise.

• Use the direct select tool

(white arrow) to select text or

symbols.

• You also have layer control

on your vector data layers.

• Releasing clipping masks will

allow editing of complex line

work.

Interoperability options

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• Toolbox for KML, raster conversions – in and out

• Plugins e.g. ogr2gui_0.6 for mapinfo/arcGIS conversions.

• Hawks Analysis Tools

• ETGoowizards

• AI (Adobe Illustrator) output. Remember to use the direct select (white

cursor arrow) and release clipping masks to edit the data in AI.

ArcToolbox

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Conversion tools

Raster to shapefile conversion

Creating Feature classes

Defining projections – reprojecting

Spatial analysis tool for extracting data

Interpolation

Fields – assigning auto text/#

to fields

Analysis tool – Extract (clip)

Geoprocessing

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Other tricks

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• 2 linked layers – for insert maps with correct scale box

• Clipped data from a shape e.g. coastlines for good images

• Masking data permanently or just colour mask e.g. remove background

• Use of the pause and refresh buttons

• Cross section construction plugin

• Elevation and other geophysical data available at:

GADD at GA