Collection and Visualization of DGPS Bathymetric Data

Sean Hartnett - Geographer - University of Wisconsin - Eau Claire www.uwec.edu/hartnesg

 Abstract

This paper describes the creation of bathymetric maps utilizing Trimble ProXR DGPS and ArcGIS. Data collection begins with the integration of depth soundings with DGPS positional data. In ArcGIS this data is processed and merged into a point data file of lake bottom elevations. In ArcScene, the lake DEM is combined with adjacent land-based DEMs and both are used to render TINs or GRIDs. ArcScene supports virtual explorations of these 3D surfaces and the draping of DOQ images over the surfaces. ArcScene also supports the integration of other types of data and the calculation of volume statistics.

 

Overview of Bathymetric Mapping Process

 

 

Data Collection -- GIS Map Processing -- PostScript Map Production

 

Collection of Bathymetric Data

Measuring Depth

Pole Weighted String Acoustic Sounders

Graphing Sounder -- Sounder with NMEA Output -- Milti-Band Sounder

 

Plotting Positional Data

dGPS to Locate Depths via Data Logger GameBoy Data Entry

 

High-Powered Sounder Lowrance X-85 and Datalogger for Trimble ProXR

GAMEBOY DATA ENTRY

MAKE DATA
DICTIONARY
of DEPTHS i.e 1,2,3 ...
 
READ DEPTHS
FROM SOUNDER
 
USE TOGGLE 
BUTTON TO SCROLL TO APPROPRIATE DEPTH
 
HIT ENTER  - WAIT TO RECORD ONE GPS POINT
 
HIT ENTER  - WAIT TO STORE POINT

 

REPEAT . . . up to 1,000 Points Per Hour
 

 

Bathymetric Data Processing

Pre-GIS Human Intensive Contour Based Methodology

Plot Transect Lines Locate Contour Depths (i.e. 5, 10. 15) on Transects

Plot Contours By hand / or SYMAP ­ SURFER ­ with significant method produced error

Digitize Contours Atlas*Draw Calculate Area of Contours Calculate Volume of Frustums

 

Current ArcMap/Spatial Analyst DEM (Point-Surface) Based Methodology

Open Depth (Point X-Y-Z) and Shore (Line) Shape Files ­ Define Projections

Merge Depth Point Files with GeoProcessing Wizard

Add and Calculate Depth and Elevation Fields (Subtract Depth from Lake Surface Elevation)

Add Land-Based DEM Point Files (X-Y-Z)

Render Depth Points and Shorelines into TIN Surface

 

CHIPPEWA RIVER dGPS DEPTH POINTS

 

CHIPPEWA RIVER dGPS DEPTH POINTS + LAND BASED DEM POINTS > RENDER TIN

Plot Contours

3D VIEW OF TIN AND CONTOURS

LAKE ALTOONA  dGPS DEPTH POINTS + LAND BASED DEM POINTS

LAKE ALTOONA TIN SURFACE

ROCHE A CRI 3D DEPTH POINTS

ROCHE A CRI 3D TIN

 

ROCHE A CRI TIN WITH DEM

ROCHE A CRI 3D VIEW

Export JPEG and PDF images

 

PostScript Map Production via Adobe Illustrator

Edit Exported JPEG images - colorize - adjust colors - adjust resolution

Place Exported JPEG and PDF images

Draw Contours with smooth curves

Add Vegetation, Cribs and Substrate Symbols

Add Text and Graphs

Finalize Layout

 

 

 

For a High ­ Resolution Image Intensive Version of this presentation ­ GO TO

http://people.uwec.edu/hartnesg

 

Author Information

Sean Hartnett, Professor of Geography, University of Wisconsin ­ Eau Claire,

P255 Eau Claire, WI 54702, 715.834.7301, fax7158366027, hartnesg@uwec.edu