GIS, GPS and Geologic Mapping
Mark Helper
helper@jsg.utexas.edu
Jackson School of Geosciences
University of Texas Austin
Outline
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Geologic mapping vs. Surveying/Sampling
Tools for mapping
Geospatial Data Product
 DGPS - Recent developments
 Field GIS/GPS Hardware & Software
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What works now (and will perhaps in the
near future)
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7/1/2016
Sources of extant geologic maps
INF 385T, M. Helper
Why Digital Mapping?
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7/1/2016
All data will eventually be digital – why not
collect it in this form?
Imposes consistency & uniformity on
observations and symbology
Potential efficiencies
Assert ownership: Analog data can be
compiled by technicians without application
of geologic principles
INF 385T, M. Helper
Why the lack of progress?
Two Possible Reasons:
1. Most field applications
are designed for
surveying/inventorying
and/or navigating
2. Geological maps are
among the most complex
of all geospatial data;
mapping is not surveying.
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Surveying and Sampling:

Mechanical exercises

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Objective exercises

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Location(s) prescribed at outset
Where am I; what am I observing
Well suited to automation – tools are
paramount, intellect less so
Largely 2-D exercises
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INF 385T, M. Helper
Geologic Mapping Is:
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An Intellectual Exercise
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Explore, discover, record
A Melding Of:
1.
2.
3.
properly surveyed locations
controlled extrapolations
INTERPRETATION, guided by:


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7/1/2016
Geologic principles (Superposition, Original
Horizontality, rule of V’s, Walther’s Law, etc.)
Experience, Intuition (bias)
An Exercise in 3-D Visualization
INF 385T, M. Helper
Geologic Map: The Austin West
Quadrangle
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7/1/2016
Colors denotes
rock types and
ages
Lines indicate
faulted or
depositional
boundaries
between rock types
INF 385T, M. Helper
Successful Mapping Requires:

Recording observations and interpretations
WHILE IN THE FIELD
A visual record of observations guides
interpretation
 Extant observations dictate mapping strategies
 Decisions are best when all evidence is at hand

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Multiple working hypotheses
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7/1/2016
Reconciling observation with interpretation
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This map records all visible features
but…
…has not been
interpreted.
…can not be
interpreted
without another
visit to the site.
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INF 385T, M. Helper
What Tools Are Available?

Geospatial Data Products
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DGPS
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7/1/2016
Precise location techniques
GIS Software

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Orthorectified aerial photos or satellite images
(DOQs) and digital topo. maps (DRGs)
3-D elevation models (DEMs, hillshades)
Database schemas and flexible tools for capturing,
editing, storing feature locations and attributes
Field Hardware that integrates these
INF 385T, M. Helper
What Tools Are Available?

Geospatial Data Products
Orthorectified aerial photos (DOQs) and
digital topo. maps (DRGs)
 3-D models (DEMs)
 Satellite imagery

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Geospatial Data Products
DOQ
DRG
7/1/2016
DEM
“Hillshade” of DEM
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Airborne LIDAR Elevation Models
?
Glen Rose Lm.
Edwards Lm.
?
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1.8m LiDAR hillshade
Geology on Hillshade - Layering
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UTM
Grid
4949600
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DRG
UTM NAD83 13N
Spence 7.5 ' Quad.
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200
0
200
400
600
Meters
1:12,000
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Helper
Contour
Interval =M.
20 feet
MN
Õ
True N is ~1 degrees
East of grid N.
16 degrees
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Derivative Base Maps
UTM
Grid
4949600
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4948500
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DRG on Hillshade
UTM NAD83 13N
Spence 7.5 ' Quad.
200
0
200
400
Meters
1:12,002
7/1/2016
600
Contour
IntervalM.
= 20Helper
feet
INF
385T,
MN
Õ
True N is ~1 degrees
East of grid N.
16 degrees
721 800
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Derivative Base Maps
Derivative Base Maps
DOQ on Hillshade
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Derivative Base Maps
0.3 m True color DOQ – USGS “New Product”
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Base Map Services
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7/1/2016
With high bandwidth, get base map data to
mapping device while mapping – base map
data not stored locally
Commercially available services, some free
(e.g. Google, Bing)
In practice - urban areas only, high risk for
little reward
INF 385T, M. Helper
What Tools Are Available?

Differentially-corrected GPS (DGPS)
Precise locations in any coordinate system
 Now available free, in real time, nearly
everywhere in continental US

Base: known position
Rover: unknown position
Baseline
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INF 385T, M. Helper
GPS Milestones
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1978: First 4 satellites launched
1983: GPS declassified
1989: First hand-held receiver
1991: S/A activated
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DGPS now essential for surveying and mapping
1993: GPS constellation fully operational
• I get a hand-held receiver
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1995-1996: First hand-held, “mapping-grade”
receivers (DGPS-enabled, w/data dictionary)
• DGS gets 2, and buys 2 more 3 years later
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INF 385T, M. Helper
GPS Milestones, cont.
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1996-1998: GPS on a microchip
•
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1997: First $100 hand-held receiver
1999: USCG DGPS service operational
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Free real-time DGPS for areas near waterways
2000: S/A off

Detailed mapping with an inexpensive receiver now possible.
•
•
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UT senior thesis student completes first map with DGPS
DGS buys 10 WAAS-enabled e-Trex receivers
DGS begins teaching GIS/GPS course
2003: FAA commissions WAAS
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Free national DGPS coverage
•
7/1/2016
DGS/CNS purchases 35 more e-Trex
INF 385T, M. Helper
Important Developments, DGPS
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7/1/2016
USCG DGPS beacon service (1999)
Deactivation of Selective Availability
(S/A) (2000)
Commissioning of FAA Wide Area
Augmentation System (WAAS) (2003)
INF 385T, M. Helper
Deactivation of Selective Availability
100
100
S/A Off, 5-3-2000
Latitude (m)
Latitude (m)
S/A On, 5-1-2000
0
0
~25 m
~100 m
- 100
- 100
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0
Longitude (m)
100
- 100
- 100
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0
Longitude (m)
100
Commissioning of (WAAS)
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7/1/2016
DGPS corrections broadcast from
geostationary satellites
INF 385T, M. Helper
What kind of GPS receiver do I need?
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7/1/2016
What resolution do you require?
Will you collect feature attributes with
locations?
Will it be a stand-alone device or cabled to a
computer/PDA?
INF 385T, M. Helper
R.F. map scale at 0.5 mm
GPS Resolution and Map Scales
1:200 K
100 m
50 - 20 K
10 – 25 m
6-2K
<1:2 K
S/A off (2000)
DGPS
WAAS (2003)
1.5 – 3 m
15 - 4 K
DGPS beacon
1–3m
(e.g. USCG)
DGPS
carrier-phase
(e.g. RTK)
<1 m
3
6
12
25
100
Horizontal Resolution, meters
7/1/2016
S/A on (1991)
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GPS Resolution and Map Scales
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Low-Tech Mapping
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Gridded maps/photos, pencil, GPS receiver
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4949600
4949500
4949400
4949300
4949200
4949100
4949000
4948900
4948800
4948700
4948600
4948500
4948400
4948300
UTM NAD83 13N
Spence 7.5 ' Quad.
200
0
200
400
Meters
1:12,002
Contour Interval = 20 feet
7/1/2016
600
MN
Õ
True N is ~1 degrees
East of grid N.
16 degrees
INF 385T, M. Helper
High-Tech Mapping Tools
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Field Hardware
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Windows CE or PocketPC devices
Outdoor tablet computers – Win XP
Field GIS/GPS Software

ESRI Software
 ArcPad
 ArcMap
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INF 385T, M. Helper
High-Tech Mapping Tools
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Field Hardware
 Mobile
Phones
 Ipad or other tablet
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Field GIS/GPS Apps.
Apple OS, Android OS,
Windows Mobile
 Surveying Apps.
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7/1/2016
INF 385T, M. Helper
GPS-equipped Windows Devices
• Small, low res.,
color screens
• Limited CPU
• Resistive stylus pen
• Up to 12 hrs. battery
life
• Light, portable
• Variably rugged
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Small, low res., color screens
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Outdoor viewing difficult
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Outdoor Tablet Computers
• Large, outdoor-viewable,
high res. color screens
• Inductive stylus pen
• 3-4 hr. battery life
• Heavy, rugged
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INF 385T, M. Helper
GIS-GPS Software
ArcPad
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Uses standard data
formats – shapefile,
tif, SID, etc.
Good GPS support
Supports custom
forms
Well-integrated with
ArcGIS products
Easy to use
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Tablet Running ArcPad
Qal
pCdm
pCcm
GPS
Location
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ArcGIS - ArcMap Software
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7/1/2016
Desktop software in the field
Powerful Drawing tools – best feature
Edit Geodatabases in the field
Minimal GPS capture tools
GIS background required
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Tablet Running ArcMap
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Windows Journal on Tablet
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Panorama Capture, Field Annotation
Section B
Section A
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06/08/06
Integrated Field Notes and Photos
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What works?
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It all does, sometimes
Rated by field efficiency, ease of use and
reliability for mapping:
1. Gridded paper maps and GPS
2. Windows CE GPS device running ArcPad
(i.e. Trimble GeoXT or XM, Yuma, Nomad)
3. Tablet running ArcPad
4. Tablet running ArcMap
5. Recently, Ipad with GIS Pro software
Pace of hardware and software changes are
still extremely rapid
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A few important portals for geologic
maps:
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7/1/2016
MapView - NGMDB : for the US
only, best extant access to the
national archive of geoscience
maps. 90,000+ maps.
OneGeology – International effort to
create and share dynamic digital
geology map data for the world.
WMS service compiler.
INF 385T, M. Helper