Digital Elevation Model (USGS DEM), SW quadrant of Lake Charles Southeast quadrangle, Louisiana, UTM 15 NAD83, Louisiana, UTM 15 NAD83, Louisiana Federal Emergency Management Agency (FEMA) Project - Phase 2 of Louisiana LIDAR Data Development: Calcasieu Parish, Louisiana under the Watershed Concepts contract number EMT-2002-CO-0048, Task Order 012. [3009364sw.dem]

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Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: Watershed Concepts
Publication_Date: 2003
Title:
Digital Elevation Model (USGS DEM), SW quadrant of Lake Charles Southeast quadrangle, Louisiana, UTM 15 NAD83, Louisiana, UTM 15 NAD83, Louisiana Federal Emergency Management Agency (FEMA) Project - Phase 2 of Louisiana LIDAR Data Development: Calcasieu Parish, Louisiana under the Watershed Concepts contract number EMT-2002-CO-0048, Task Order 012. [3009364sw.dem]
Description:
Abstract:
This is a Digital Elevation Model (DEM) over the SW quadrant of the Lake Charles Southeast quadrangle, Louisiana. The data were derived from LIDAR measurements performed in 2002, and are presented at a elevation posting interval of five meters. The model is in USGS (non-SDTS) DEM format.

These data were produced for the Louisiana Federal Emergency Management Agency (FEMA) Project - Phase 2 of Louisiana LIDAR Data Development: Calcasieu Parish, Louisiana under the Watershed Concepts contract number EMT-2002-CO-0048, Task Order 012.

Purpose:
DEM data are useful for terrain analysis and modeling including slope and aspect calculations. They may be used to produced shaded relief maps and contour maps.
Supplemental_Information:
The metadata for this image are encapsulated into several documents. The metadata are not complete if you did not receive the following files along with the data set:

dem_3009364sw.mtd - this metadata in mp (metadata parser) compatible ASCII text form
dem_3009364sw.html - this metadata in HTML form
dem_3009364sw_faq.html - this metadata presented as Questions and Answers
dem_3009364sw.sgml - this metadata in SGML form
dem_3009364sw.xml - this metadata in XML form
The information depicted on this map are the results of the survey on the dates indicated and can only be considered as indicating the general conditions existing at the time.
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 200202
Currentness_Reference:
Approximate date of LIDAR survey used to build the source data for this data set
Status:
Progress: complete
Maintenance_and_Update_Frequency: none planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -90.5625
East_Bounding_Coordinate: -90.5000
North_Bounding_Coordinate: +30.9375
South_Bounding_Coordinate: +30.8750
Keywords:
Theme:
Theme_Keyword_Thesaurus: none
Theme_Keyword: framework
Theme_Keyword: DEM
Theme_Keyword: digital elevation model
Theme_Keyword: elevation
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: Louisiana
Place_Keyword: Calcasieu Parish
Access_Constraints: none
Use_Constraints:
These unaltered data may not be redistributed without all of the elements of the metadata listed in the Supplemental_Information section of this metadata document.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Watershed Concepts
Contact_Person: David Key, P.E
Contact_Address:
Address_Type: Mailing and physical address
Address: 3333 Regency Parkway, Suite 120
City: Cary
State_or_Province: North Carolina
Postal_Code: 27511
Contact_Voice_Telephone: (919)868-5155

Data_Quality_Information:
Logical_Consistency_Report:
The DEM was produced with an origin at an even increment of the DEM point spacing to allow adjacent tiles to be appended without resampling.

One of the primary goals of this project was to produce higher accuracy elevation data than was available for the Amite River Basin. Because of the wide array of uses for the data products, many standards had to be taken into consideration for data production. Among these were the FEMA standard for LIDAR capture and data processing, and the USGS standard for Digital Elevation Models. With regard to the USGS standard for Digital Elevation Models, the resolution of the data produced in this project is higher than that for which the standard guidelines were developed. Although this was the overriding goal of the project, it also requires the data follow the standard more loosely than if the data were spaced at the same intervals and resolution as regulated by the standard.

The USGS standard provides guidelines for 5 primary types of DEMs. The main difference between the types is the geographic coverage of the data and the resolution of GRID values within the DEM. The smallest geographic extent and grid spacing (and thus the most accurate DEM) documented in the standard is the 7.5 minute DEM (which is a typical USGS Quadrangle). The standard states that the resolution of the 7.5 minute DEM “will have a 10 or 30 meter grid spacing”. The DEMs produced in this project are tiled to USGS Quarter Quadrangles (or ¼ of the typical 7.5 minute quad). The GRID spacing is 5-meters, as opposed to the 10 or 30 meter requirement of the standard.

It should also be noted that when these DEMs are viewed with the USGS DLG Viewer software, there are inconsistencies in the elevation data reported by the viewer. These inconsistencies have not been observed in other viewers, including ArcInfo, ArcView, ERDAS and Terramodel. The reason for the inconsistencies is that the DEM generated by ArcInfo utilizes data elements of the USGS standard that DLG Viewer does not take into account when computing elevations.

Based on the USGS "Standards for Digital Elevation Models", a DEM file is organized into a series of three records, A, B, and C. The A record contains information defining the general characteristics of the DEM, including its name, boundaries, units of measurement, minimum and maximum elevations, number of B records, and projection parameters. Each B record consists of an elevation profile with associated header information, and the C record contains accuracy data. Each file contains a single A and C record, while there is a separate B record for each elevation profile.

Two data elements in particular appear to cause the rendering inconsistencies with the DLG Viewer software. The data elements are the z resolution (data element 15, record b) and the local datum for the profiles (data element 4, record b). The DLG viewer appears to ignore one of the math expressions or uses a default value to compute the elevations. The other viewers listed above can do the math and show the z-values properly. In these viewers, elevations are computed by multiplying the z-values by the z resolution and then adding the local datum value. By either using a default value for the z resolution or datum, or not taking one of these elements into consideration when computing the elevation, the DGL Viewer is not displaying the correct elevation.

According to the USGS "Standards for Digital Elevation Models" the z resolution does not have to be a multiple of 10 (e.g 1, .1, .01, etc.). This is the case for the DEMs created by ArcInfo for this project (e.g. .286508). As far as the local datum for the profiles, ArcInfo uses the lowest elevation in the file. According to the USGS Standard, the local datum does not have to be set to zero.

Completeness_Report:
The DEM has been clipped to the area of the 3.75 minute cell comprising the SE of the Lake Charles Southeast. All lattice points outside this area that comprise the balance of the minimum bounding rectangular area in UTM coordinates have the 'no data' elevation value of -32767.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: Wayershed Concepts
Publication_Date: 2003
Title:
Digital Elevation Model (ArcInfo lattice), SW quadrant of Lake Charles Southeast quadrangle, Louisiana, UTM 15 NAD83, Louisiana Federal Emergency Management Agency (FEMA) Project - Phase 2 of Louisiana LIDAR Data Development: Calcasieu Parish, Louisiana under the Watershed Concepts contract number EMT-2002-CO-0048, Task Order 012. [lat_3009364sw]
Type_of_Source_Media: computer file
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 200202
Source_Currentness_Reference: Approximate date of LIDAR survey data used to build lattice
Source_Citation_Abbreviation: LAT_3009364sw
Source_Contribution: Regular lattice of elevation values
Process_Step:
Process_Description:
LAT_3009364sw was processed with ArcInfo LATTICEDEM to produce a USGS format DEM.
Process_Date: 2003
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: 3001, Inc.
Contact_Position: LIDAR Manager
Contact_Address:
Address_Type: mailing and physical address
Address: 5525 Mounes, Suite 102
City: New Orleans
State_or_Province: LA
Postal_Code: 70123
Contact_Voice_Telephone: (504) 733-3001
Process_Step:
Process_Description: Metadata imported.
Source_Used_Citation_Abbreviation: N\A
Time_of_Day: 14373200

Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Point

Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name: Universal Transverse Mercator
Universal_Transverse_Mercator:
UTM_Zone_Number: 15
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.9996
Longitude_of_Central_Meridian: -93.000000
Latitude_of_Projection_Origin: +00.000000
False_Easting: 500000
False_Northing: 0
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 5
Ordinate_Resolution: 5
Planar_Distance_Units: Meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137
Denominator_of_Flattening_Ratio: 298.257
Vertical_Coordinate_System_Definition:
Altitude_System_Definition:
Altitude_Datum_Name: North American Vertical Datum of 1988
Altitude_Resolution: 0.01
Altitude_Distance_Units: Survey Feet
Altitude_Encoding_Method:
Explicit elevation coordinate included with horizontal coordinates

Metadata_Reference_Information:
Metadata_Date: 20030620
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: 3001, Inc.
Contact_Address:
Address_Type: mailing and physical address
Address: 5525 Mounes Street, Suite 102
City: New Orleans
State_or_Province: LA
Postal_Code: 70123
Contact_Voice_Telephone: (504) 733-3001
Contact_Facsimile_Telephone: (504) 734-8938
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998

Generated by mp version 2.8.2 on Wed Jun 25 11:08:34 2003