Friday, July 20, 2012

Bathymetry Mapping with ciBioBase!

At Contour Innovations, we often preach the importance of aquatic plant mapping and monitoring, but of equal importance and capability is ciBioBase bathymetric mapping features.  ciBioBase comes with many features that automate the tedious, mundane, yet highly technical GIS processes associated with creating a bathymetric map.  Water resource and lake managers and researchers should be spending their time and talents focusing on thorny management problems, not compiling and managing volumes of data and trying to map them in GIS.  The science of acoustic bottom detection and GIS mapping has been extensively tested, verified, and proven with standard methods.  We automate this.

Because ciBioBase maps only areas you cover up to a 25-m buffer outside of your track, you are assured that maps do not include extrapolated data.  40-m spacing of transects with a criss-cross design assures you that you will get complete coverage and smooth contours (Figure 1). 
Figure 1. Transect coverage showing a "criss-cross" design to assure a high quality bathymetric map.

The Trip Replay feature in ciBioBase further allows you to see disruptions in the contours (Figure 2).  As in the case with Figure 2, there was a temporary disruption in the transducer signal, thus giving an erroneous depth (Figure 2 and 3).  In ciBioBase, these erroneous depths can be edited out; thus creating a smoother, more accurate bathymetric map and associated statistics.
Figure 2. Desktop verification of bathymetric outputs with ciBioBase's Trip Replay feature.
Figure 3. Areas of disrupted signal can be deleted and the trip reprocessed for a more accurate and smooth bathymetric map.
Other times, these little “donuts” occur because depths temporarily enter a different contour level (e.g., 3ft contours with series depths = 5.99, 6.0, 5.99, 5.98, etc).  Although the 6.0 depth is likely legit, it may be more aesthetically pleasing to remove the 6.0 depth to prevent the creation of a 6ft donut hole.

Once you are happy with the output with individual trips, you can merge them in ciBioBase to create a uniform output (Figure 4).
Figure 4.  Merging function in ciBioBase that allows users to merge individual files or trips into a single, uniform map.
Tying Bathymetry to a Benchmark Elevation
When mapping bathymetry, it may be important to tie the water level to a benchmark water level elevation.  In our Minnesota Lake example, we went to the Minnesota Department of Natural Resource’s Lakefinder website and found important water level information (Figure 5).  On 6/5/2012, we surveyed McCarron’s Lake in Ramsey County, MN.  On 6/7/2012, the elevation-corrected water level reported by citizen volunteers was  840.84 ft above sea level.  The Ordinary High Water Level  (OHW) benchmark for McCarron’s is 842.21 ft (Figure 5).  Using the Data Offset feature in ciBioBase (Figure 6), we can simply add 1.37 ft (elevation correction) plus 1 ft (transducer correction) to get a bathymetric map that is corrected to the OHW (Figure 7).  This eliminates water level as a confounding variable with repeated bathymetric surveys on the same waterbody.  The final products are high resolution, blue-scale imagery as seen in Figure 7 (up to 1-ft contours) or the actual point and grid data that can be imported into any third party GIS or statistical software (Figure 8).
Figure 5. Water level information for McCarron's Lake in Ramsey County, Minnesota USA.
Figure 6. Data Offset feature in ciBioBase that allows users to correct their bathymetric data to a benchmark water level and transducer depth.
Figure 7. Bathymetric imagery with resolution (both bottom and pixel) that can be controlled by the user.
Figure 8. Export point data along your traveled path or the kriging interpolated grid for use in third party GIS or statistical software.

Life is good in the cloud...

Because of the centralized, cloud-based platform of ciBioBase, we see trip uploads into the system from all types of lakes, ponds, and reservoirs throughout the country and even abroad; so our acoustic and geostatistic algorithms have seen it all!

See for yourself in our demo account at ciBioBase.com.  In the login page, enter demo@cibiobase.com and “demo” for the password.  Operators are standing by to answer any questions you may have!

Monday, July 9, 2012

Lake Mapping and 800 kHz DownScan

ciBioBase Now Offering 800 kHz DownScan in its dynamic Trip Replay feature.



Trip Replay is taking a leap forward with the new option to view your data using the 800 kHz DownScan option when recording with the StructureScan™ add-on.  Anyone that has been uploading data gathered with StructureScan™, by logging all channels, can now view past and future trips with this new feature.

You may have seen our earlier posts about the ciBioBase Trip Relay feature.  Your raw data collection is automatically processed by our powerful cloud servers and fully mapped with krigging algorithms and other geo-statistical considerations. Once processed, you can then replay the entire trip, watch your boat travel along your transects, and ground truth the % BV heat map with the water column cross section (on the right side of the image above).   This feature allows our customers to verify every trip output for accuracy and provide objective evidence for anyone that questions your aquatic vegetation maps!

The power and accuracy of the Lowrance™ HDS StructureScan™ allows us to offer a new and amazing cross-section view (DownScan) of the water column for each trip in the Trip Replay feature.  As you can see from the images below, this feature provides amazing views of bottom and vegetation.  It is even possible to notice changes in vegetation types or habitat cover type under your boat.  With our waypoint feature, you can identify vegetation transition zones and areas of interest for typing and delineation.



Please let us know if you would like to add StructureScan™ to your current data collection hardware.  Although not mandatory for using ciBioBase, this option can be added to any HDS™ system at any time for great views underwater.  For details on using or recording StrucutreScan™ please request a copy of our Standard Operating Procedures.


Another great feature added to the powerful ciBioBase System.

ABOUT ciBIOBASE

ciBioBase was engineered to provide automated cloud based GIS, aquatic vegetation mapping and historical trend tools for aquatic habitat analysis.  CI BioBase leverages log file formats recorded to SD cards using today’s Lowrance™ brand depth finders and chart plotters.  Data you collect while on the water is uploaded to an online account where it is processed by our servers automatically.   We rely on automation to make vegetation mapping cost effective by reducing the technical skills, staff, and hours to produce vegetation abundance maps from raw sonar collection. With the human element gone, you get accurate and objective mapping at lightening speeds!

Check out more anytime at ciBioBase.com and on our ciBioBase BLOG