Contact

Bret M. Webb, Ph.D., P.E., D.CE
Professor
University of South Alabama
150 Jaguar Drive, SH3142
Mobile, AL 36688 USA
Phone: (251) 460-6174
Fax: (251) 461-1400
Email: bwebb@southalabama.edu

Research Positions

None available at this time

Current Research Assistants

SE Students
Garland Pennison

 

MSCE Students
Patrick Hautau
Marshall Hayden
Kate Haynes
Justin Lowlavar
Vijaya Satya Lohitha Mukkamala
Jackie Wittmann

 

Undergraduate Students
Derek Kelly
Rh'Monte Wilson

Former Students

MSCE Students
Bryan Groza (2016)
Kari Servold (2015)
Chris Marr (2013)
Richard Allen (2013)
Miyuki Matthews (2012)

 

Post Docs
Jon Risinger
Jungwoo Lee

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HydroSurveyor

I use SonTek’s HydroSurveyor (HS) software on our Jag Ski when collecting bathymetric data. I prefer to use this instead of their RiverSurveyor Live software because of its line planning, navigation, and absolute RTK capabilities. One of the nice things about HS–when it was released–was its ability to reference aerial imagery via online map tile servers. However, this capability disappeared in early 2017 when the MapQuest tile server ceased to exist.

Not wanting to lose the ability to plan surveys with current aerial imagery in the background, I decided to figure out how to import imagery. While this capability of HS has always existed, and while it is documented in the user manual, I never had the patience to figure it out. Until I had to! Here is a step-by-step process that I followed to make this work. Note that I will reference the GIS software “QGIS” in my steps. This stands for Quantum GIS (click here). Any GIS software could be used as a substitute, but I prefer to use QGIS because it works across all computing platforms and I commonly have to swap back and forth between a Mac and a PC.

 

  1. Download NAIP imagery from USGS National Map Viewer (click here)
  2. The image will be a JPEG2000 (jp2). Images after 2013 are projected in WGS 1984 Web Mercator Auxiliary Sphere projection (EPSG 3857), which is exactly what you need for the HS software.
  3. Open your image in QGIS, define the CRS as EPSG 3857 (WGS84 Mercator)
  4. Save your file with a new name as a rendered GTIFF using the same CRS (EPSG 3857)
  5. In QGIS, go to Raster / Projections / Extract Projection. Select your file created above (tiff) and then process.
  6. Rename the world file with extension “tfw” instead of “wld”. (Note that the remaining steps will not work unless you complete this one. The HS software requires a world file, but you don’t get one when you download the imagery from the USGS National Map Viewer.)
  7. Open HydroSurveyor, select Tasks / Import Georeferenced Image, and then select your tiff file(s).
  8. Select WGS-84 Mercator in the following window.
  9. Save the tiled data with a new name.
  10. In HydroSurveyor, click “Add Layer” and then “Browse for File” … select your tile files.
  11. Note that you may need to expand your image layer using “>>” and then select “zoom to layer” in order to see your imagery.

 

Do you have to use imagery from the USGS National Map Viewer? No, not at all. Any georeferenced aerial imagery will work so long as you can 1) reproject it to WGS84 Mercator (EPSG 3857) and 2) extract/create/obtain the image world file. That said, another good option for imagery is TerraServer, but those images can be expensive.