USGS
 Environmental Geochemistry and Sediment Quality in Lake Pontchartrain
   

GIS Layers and Metadata

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mapinfo workspaces and ArcView project files are available here to demonstrate the intended display parameters for most of the GIS layers. The CD-ROM is organized with the layers in the correct directories so that these project files can reference them.

The matrix below lists individual GIS layers that were used in many of the figures in the sediment database section. They were generated as .tab files in mapinfo and then exported to mapinfo Interchange Format (.mif & .mid) and converted where possible to ArcView shapefiles (.shp). Each layer is a downloadable .zip archive. [Note that most of the mapinfo zipped files have the same archival name as the ArcView zipped files, so if you are downloading both, you may want to create two separate directories.]  The mapinfo archives contain a .mif (graphic data) and a .mid (tabular data). The ArcView archives contain a .shp, .dbf, and .shx, or in the case of the raster images, a .tif and a .tfw (tif world file for registering the image).  Also listed in this table is metadata describing the feature types included in each layer (point, line, polygon, or raster), a verbal description of the layer's content, the source from which the data was obtained or generated, the projection in which the data is stored, and the approximate bounding coordinates of the layer.

Lead199, Zinc199, and Sand199 are examples of data extracted from the database for analysis. They were created from Access queries and then opened in a GIS. For future publications, additional layers such as these will be created and inspected for patterns of sediment contamination. Some layers (ie.: Water, Land, NewOrl, Fullgrid, DEMs) are provided as a backdrops or geographic references for the sediment data. Other layers may be more valuable once they are further processed. For example, a point file of bathymetric soundings from Lake Borgne has been included for its raw data, but once gridded and contoured, it would provide a more illustrative map of the lake bottom.

Zip files containing all the available layers are offered here:
mapinfo tables ArcView shapefiles and tifs

Individual layers:

MAPINFO FILES

ARCVIEW FILES

FEATURE TYPE

DESCRIPTION

SOURCE

PROJECTION

APPROX. BOUNDS E-W

APPROX. BOUNDS S-N

maur.zip

maur.zip

Point

Lake Maurepas bathymetry

digitized from NOAA navigation chart 11369

Geographic (Lat/Long)

90.38W to 90.6W

30.16N to 30.35N

maurcont.zip

maurcont.zip

Line

Contoured bathymetry for Lake Maurepas

contoured Maurepas bathymetry using Vertical Mapper

Geographic (Lat/Long)

90.38W to 90.6W

30.16N to 30.35N

maurshor.zip

maurshor.zip

Line

Shoreline of Lake Maurepas

used Lat/Longs for Lake Maurepas shoreline from water2.mif

Geographic (Lat/Long)

90.3W to 90.6W

30.16N to 30.35N

pontbath.zip

pontbath.zip

Point

Lake Pontchartrain bathymetry

digitized from NOAA navigation chart 11369

Geographic (Lat/Long)

89.73W to 90.44W

30.0N to 30.4N

pontcont.zip

pontcont.zip

Line

Contoured bathymetry for Lake Pontchartrain

contoured Pontchartrain bathymetry using Vertical Mapper

Geographic (Lat/Long)

89.73W to 90.43W

30.0N to 30.4N

pontshor.zip

pontshor.zip

Line

Shoreline of Lake Pontchartrain

used mapinfo's autotrace function on L. Pontchartrain in "water2.tab"

Geographic (Lat/Long)

89.62W to 90.44W

30.0N to 30.4N

borgbath.zip

borgbath.zip

Point

Lake Borgne bathymetry

NOAA's Geophysical Data System for Hydrographic Survey Data (CD-ROM data set) v 3.3

Geographic (Lat/Long)

89.42W to 89.86W

29.85N to 30.25N

stations.zip

stations.zip

Point

Station locations in pontdb database

USGS pontdb.mdb (this volume)

Geographic (Lat/Long)

88.5W to 92.9W

29.0N to 30.0N

sand199.zip

sand199.zip

Point

Sample locations showing sand percent

sample locations as of January 1999 with sand percent and source noted

Geographic (Lat/Long)

88.51W to 92.87W

29.02N to 30.42
lead199.zip lead199.zip Point Lead concentrations extracted from USGS pontdb.mdb (this volume) Geographic (Lat/Long) 88.51W to 92.87W 29.02N to 30.42
zinc199.zip zinc199.zip Point Zinc concentrations extracted from USGS pontdb.mdb (this volume) Geographic (Lat/Long) 88.51W to 92.87W 29.02N to 30.42

land.zip

land.zip

Polygon

Land around Lakes Maurepas, Pontchartrain and Borgne

created outer polygon from NOAA's Gc80_04

Geographic (Lat/Long)

89.47W to 90.65W

29.84N to 30.5N

water.zip

water.zip

Polygon

Maurepas, Pontchartrain, Borgne, Mississippi River

created inner polygons from NOAA's Gc80_04

Geographic (Lat/Long)

89.3W to 90.67W

29.8N to 30.4N

new_orl.zip

new_orl.zip

Polygon

Urban area of New Orleans and Kenner

digitized from NOAA navigation chart 11369

Geographic (Lat/Long)

89.9W to 90.3W

29.9N to 30.1N

cause-bt.zip

  

Line/polygon

Causeway and Bayou Trepagnier

digitized from NOAA navigation chart 11369

Geographic (Lat/Long)

90.09W to 90.4W

30.0N to 30.37N

borderla.zip

borderla.zip

Line

State border of Louisiana

LandView point file converted to line using mapinfo

Geographic (Lat/Long)

88.8W to 94.1W

28.9N to 33.1N

gc80_02.zip

gc80_02.zip

Line

Gulf of Mexico coastline (SW Louisiana)

NOAA's medium resolution digital vector shoreline http://seaserver.nos.noaa.gov/projects/shoreline/shoreline.html

Geographic (Lat/Long)

91.07W to 93.45W

29.39N to 31.05N

gc80_03.zip

gc80_03.zip

Line

Gulf of Mexico coastline (S-central LA)

NOAA's medium resolution digital vector shoreline http://seaserver.nos.noaa.gov/projects/shoreline/shoreline.html

Geographic (Lat/Long)

89.95W to 91.38W

29.04N to 29.98N

gc80_04.zip

gc80_04.zip

Line

Gulf of Mexico coastline (SE Louisiana)

NOAA's medium resolution digital vector shoreline http://seaserver.nos.noaa.gov/projects/shoreline/shoreline.html

Geographic (Lat/Long)

88.81W to 91.27W

28.92N to 30.48N

area_cd.zip

  

Line/polygon

Subdivision of Southeastern LA estuarine areas by letter codes used as a general area indicator

digitized on screen using other GIS layers as a guide; note that the areas along the shore extend inshore a bit to ensure that all sample locations were captured

Geographic (Lat/Long)

89.17W to 90.61

29.37N to 30.39N

squares.zip

  

Polygon

Numerical grid covering Lakes Maurepas, Pontchartrain, and Borgne; designed for systematic comparison of sediment parameters by location

generated with mapinfo's GridMaker

Geographic (Lat/Long)

89.36W to 90.61W

29.81N to 30.42N

fullgrid.zip

  

Line

Graticule at 0.1 degree covering Lakes Maurepas, Pontchartrain and Borgne

generated with mapinfo's GridMaker

Geographic (Lat/Long)

89.47W to 90.65W

29.84N to 30.5N

batr_dem.zip

batr_dem.zip

Raster

Digital Elevation Model of Baton Rouge area (NW of 4)

1:250,000-scale USGS DEMs downloaded from http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_dem

Geographic (Lat/Long)

90.0W to 91.0W

30.0N to 31.0N

newo_dem.zip

newo_dem.zip

Raster

Digital Elevation Model of New Orleans area (SW of 4)

1:250,000-scale USGS DEMs downloaded from http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_dem

Geographic (Lat/Long)

90.0W to 91.0W

29.0N to 30.0N

mobl_dem.zip

mobl_dem.zip

Raster

Digital Elevation Model of Mobile area (NE of 4)

1:250,000-scale USGS DEMs downloaded from http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_dem

Geographic (Lat/Long)

89.0W to 90.0W

30.0N to 31.0N

bret_dem.zip

bret_dem.zip

Raster

Digital Elevation Model of Breton Sound area (SE of 4)

1:250,000-scale USGS DEMs downloaded from http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_dem

Geographic (Lat/Long)

89.0W to 90.0W

29.0N to 30.0N
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