Schaefer, J.R.
Wallace, K.L.
Kassel, C.M.
2008
Preliminary bathymetric map of Mother Goose Lake, Alaska Peninsula
vector digital data
Raw Data File
RDF 2008-3
Fairbanks, Alaska - USA
State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys
http://dx.doi.org/10.14509/16301
In preparation for bottom sediment coring at Mother Goose Lake, bathymetric data was collected using a Lowrance Sonar "fishfinder" (model LcX-17M) in August 2006 and August 2007. A 5-meter bathymetric contour map of the lake bottom was constructed using the GPS-sonar data in conjunction with field observations. The contour data and GPS location and depth data are provided in ESRI shapefile format for use in Geographic Information System (GIS) software.
The purpose of this bathymetric data release is to provide scientific collaborators who are working on the Chiginagak volcano acid flood event, such as geologists and fisheries biologists, with depth information of Mother Goose Lake.
The layers listed below are present as ArcGIS shape files. Attribute information for the following layers (entities) is included in this metadata file under the "Entity_and_Attribute_Information" section. Each layer is listed and described in detail under its own heading starting "Entity_Type_Label." Layers include:
>MGL_islands_polyline Outline of the islands in Mother Goose Lake.
>MGL_shore_polyline Outline of the Mother Goose Lake shoreline.
>MGL_contour_5m_polyline 5-meter bathymetric contour map of Mother Goose Lake.
>MGL_gps_depth_point Lat-Long-Depth point file of data collected at Mother Goose Lake used to derive the bathymetric map.
20060824
20060825
ground condition
Unknown
-157.403722
-157.233482
57.231361
57.178854
ISO 19115 Topic Category
geoscientificInformation
None
Bathymetry
Lacustrine
Geographic Names Information System
Alaska Peninsula
Chiginagak
Mother Goose Lake
Ugashik Quadrangle
This report, map, and/or dataset are available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).
Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. User specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys.
State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys
GIS Data Manager/Cartographer
mailing and physical
3354 College Road
Fairbanks
AK
99709-3707
(907) 451-5029
(907) 451-5020
(907) 451-5050
dggspubs@alaska.gov
You may view our web site at http://www.dggs.alaska.gov for the latest information on available data. Please e-mail your questions and data requests when possible since our web site and e-mail address will remain current even if our phone number and mailing address change.
MGL_bathymetry.jpg
Bathymetric contour map of Mother Goose Lake
JPEG
Microsoft Windows XP SP2. The original data set was created in MapInfo Professional 8.0 then converted to ESRI shapefiles using the MapInfo Universal Translator.
Attributes in this dataset consist of positional information reported in latitude and longitude (decimal degrees in both NAD27 and NAD83 datums), and depth information reported in feet and meters. Original latitude, longitude, and depth attributes were recorded digitally by the Lowrance GPS-sonar unit. Original location information was recorded in a Mercator projection with the WGS84 datum. Depth in feet was converted to depth in meters by applying a conversion factor of 0.3048. The resulting data is in file MGL_gps_depth_point. Attributes in the bathymetric contour data file MGL_contour_5m_polyline consist of labels of depth in meters and were added manually as the polylines were constructed in a GIS from the MGL_gps_depth_point file.
not applicable
This dataset includes preliminary bathymetric data collected over a 2-day period in August of 2006 and a 5-day period in August 2007. The footprint of the GPS-sonar track data used to derive the contour map is small, thus the contour map represents a generalized illustration of the true bathymetry of Mother Goose Lake.
GPS-sonar data was collected with a Lowrance "fishfinder" (model LcX-17M) with a positional accuracy of approximately 15 meters. However, after mapping the sonar data in a GIS in conjunction with a vector shoreline constructed from Landsat imagery, the position of data points appears to be up to 150m off (for example, the track data in the file MGL_gps_depth_point shows points going up onto shore.
Lowrance (model LcX-17M) GPS-Sonar data was collected at Mother Goose Lake on August 24-25, 2006 and August 15-19, 2007 . Lowrance GPS data is collected and stored in a Mercator projection with a datum of WGS84. Sonar log file data was converted to a comma-delimited text file using a free utility from Lowrance called Sonar Viewer (http://www.lowrance.com/Software/PCSoftware/sonar_viewer.asp). This text file was imported into Microsoft Excel, and the following conversion was applied to convert the Mercator WGS84 projection to Geographic decimal degree coordinates in a NAD83 datum:
Excel formula to convert Mercator WGS84 location (X,Y) to Geographic Coordinates NAD83 to (longitude, latitude) decimal degrees
Latitude
=RadToDeg*((2*ATAN(EXP(Y/SemiMinor))-PI()/2))
Longitude
=(X*RadtoDeg)/SemiMinor
Where
RadtoDeg = 57.2957795132
SemiMinor = 6356752.3142
X = Lowrance position X in Mercator WGS84
Y = Lowrance position Y in Mercator WGS84
Depth information stored in feet was converted to meters by applying a conversion factor of 0.3048. This data was then imported into MapInfo Professional 8.0 to display the depth data geospatially. The projection was converted to UTM zone 4, NAD83. Decimal degree latitude and longitude information in both NAD83 and NAD27 datums were generated by projecting and updating columns in MapInfo. Using both field observations of lake depth, and the geospatially accurate sonar data, a contour of lake depth was created by digitizing around depth points in MapInfo. The file was then exported to ESRI shapefile format using MapInfo Professional 8.0 Universal Translator.
Shoreline and Islands (MGL_shore_polyline and MGL_islands_polyline): The polylines defining both the Mother Goose Lake shoreline and island shorelines were created in MapInfo Professional 8.0 using a May 8, 2005, 30-meter-pixel-width, Landsat 7 image as the base. The Landsat image was provided in a UTM zone 4 projection with a datum of WGS84. After construction, the polyline files were reprojected in MapInfo to UTM zone 4, NAD27, before exporting to shapefile format. The Landsat 7 image was set at a zoom scale of 1:10,000 during construction of the shoreline and island polyline files.
200608
Vector
Universal Transverse Mercator
4
0.9996
-159
0
500000
0
coordinate pair
0.01
0.01
meters
MGL_contour_5m_polyline
Universal Transverse Mercator
4
0.9996
-159
0
500000
0
coordinate pair
0.01
0.01
meters
MGL_islands_polyline
Universal Transverse Mercator
4
0.9996
-159
0
500000
0
coordinate pair
0.01
0.01
meters
MGL_gps_depth_point
Universal Transverse Mercator
4
0.9996
-159
0
500000
0
coordinate pair
0.01
0.01
meters
MGL_shore_polyline
North American Datum of 1983
Geodetic Reference System 80
6378137
298.25722210088
MGL_islands_polyline.shp
1 object. Polyline defining the outline of the islands in Mother Goose Lake. This feature was not assigned any user defined attribute.
This report
MGL_islands_polyline
MGL_contour_5m_polyline.shp
Polyline file representing 10-meter bathymetric contours of Mother Goose Lake.
This report
MGL_contour_5m_polyline
contour_m
line joining points of equal depth in 5-meter intervals
This report
5
50
meters
5
See vertical accuracy report
MGL_gps_depth_point.shp
25823 points of decimal degree latitude and longitude listed in both NAD83 datum and NAD27 datum. Depth listed in both feet and meters.
This report
MGL_gps_depth_point
Depth_ft
depth, in feet, below lake surface
This report
0.4
263.639
feet
15
Large swells in the lake during data collection may result in value accuracies of up to +/- 15 feet.
Depth_m
Depth, in meters, below lake surface
This report
0.12192
80.3571
meters
5
Large swells in the lake during data collection may result in value accuracies of up to +/- 5 meters.
LongNAD83
Longitude of depth measurement in decimal degrees, NAD83 datum
This report
-157.363
-157.258
degrees
150
Attribute value accuracy reported in meters.
LatNAD83
Latitude of depth measurement reported in decimal degrees, NAD83 datum
This report
57.1805
57.2252
degrees
150
Attribute value accuracy reported in meters.
LongNAD27
Longitude of depth measurement in decimal degrees, NAD27 datum.
This report
-157.361
-157.256
degrees
150
Attribute Value Accuracy reported in meters.
LatNAD27
Latitude of depth measurement in decimal degrees using NAD27 datum.
This report
57.1812
57.226
degrees
150
Attribute Value Accuracy reported in meters.
MGL_shore_polyline
1 object. Polyline defining the shore of Mother Goose Lake. This feature was not assigned any user defined attribute.
This report
MGL_shore_polyline
Below is a brief description of the four ESRI shapefiles found in this dataset:
MGL_islands_polyline - Outline of the islands in Mother Goose Lake.
MGL_shore_polyline - Outline of the Mother Goose Lake shoreline.
MGL_contour_5m_polyline - 5-meter bathymetric contour map of Mother Goose Lake.
MGL_gps_depth_point - Point file of GPS-sonar track data used to construct the bathymetric map. Positional data is reported in decimal degrees of latitude and longitude (NAD 27 datum). Depth data is provided in both feet and meters.
This report
State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys
mailing and physical
3354 College Road
Fairbanks
AK
99709
907-451-5020
None available
907-451-5050
dggspubs@alaska.gov
8 am to 4:30 pm, Monday through Friday, except State holidays
Please view our Web site (http://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.
RDF 2008-3
The State of Alaska makes no express or implied warranties (including warranties of merchantability and fitness) with respect to the character, function, or capabilities of the electronic services or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products, any failure thereof, or otherwise, and in no event will the State of Alaska's liability to the requester or anyone else exceed the fee paid for the electronic service or product.
ArcGIS Shapefile
ESRI ArcGIS 9.x
No compression applied
http://dx.doi.org/10.14509/16301
Digital files on CD-ROM are available for $10.00 (contact information below). No fees charged for downloaded files.
Order by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). The DGGS web site (http://www.dggs.alaska.gov/) has a list of electronic data available and an order form that can be printed. Payment accepted: Cash, check, money order, VISA, or MasterCard.
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Please check the MapInfo web site (http://www.mapinfo.com/) for the latest documentation on importing ESRI shape files.
20080506
20080506
20090319
Janet Schaefer
mailing and physical
3354 College Rd
Fairbanks
AK
99709
907-451-5005
janet.schaefer@alaska.gov
FGDC Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998