NJDEP 10-meter Digital Elevation Grid of the WallKill Watershed Management Area (WMA 2)
Identification_Information
Data_Quality_Information
Spatial_Data_Organization_Information
Spatial_Reference_Information
Entity_and_Attribute_Information
Distribution_Information
Metadata_Reference_Information
Identification Information
Section Index
Citation:
Citation Information:
Originator: NJ Department of Environmental Protection (NJDEP), Office of Information Resources Management (OIRM), Bureau of Geographic Information and Analysis (BGIA)
Publication Date: 20020601
Title: NJDEP 10-meter Digital Elevation Grid of the WallKill Watershed Management Area (WMA 2)
Edition: 2002
Geospatial Data Presentation Form: raster digital data
Publication Information:
Publication Place: Trenton, New Jersey
Publisher: NJDEP
Online Linkage: http://www.state.nj.us/dep/gis/digidownload/zips/wmalattice/wma02lat.zip
Description:
Abstract:
A lattice is the ESRI GRID raster file generated from USGS DEM files. Digital Elevation Model (DEM) is the terminology adopted by the USGS to describe terrain elevation data sets in a digital raster form. The standard DEM consists of a regular array of elevations cast on a designated coordinate projection system. The DEM data are stored as a series of profiles in which the spacing of the elevations along and between each profile is in regular whole number intervals. The normal orientation of data is by columns and rows. Each column contains a series of elevations ordered from south to north with the order of the columns from west to east.
The DEM supplied from USGS is formatted as one ASCII header record (A- record), followed by a series of profile records (B- records) each of which include a short B-record header followed by a series of ASCII integer elevations per each profile. The last physical record of the DEM is an accuracy record (C-record).
7.5-minute DEM (10-meter x 10-meter data spacing, cast on Universal Transverse Mercator (UTM) projection) were merged and clipped to the watershed boundary for this data set.
Purpose:
A lattice can be used as source data to create other layers which require elevation information. Examples of layers which can be derived from a lattice include aspect, contour, hillshade, slope, flow accumulation and flow direction. It can also serve as source data for applications such as volumetric analysis, for site location of towers, or for drainage basin delineation. The DEM data was purchased by the NJ Division of Watershed Management from the USGS in 2001.
Supplemental Information:
7.5-minute DEMs have rows and columns which vary in length and are staggered. The UTM bounding coordinates form a quadrilateral (no two sides are parallel to each other), rather than a rectangle. The original files were supplied to NJ in UTM meters NAD83 and were edge matched by USGS. NJ DEP converted the DEM's to lattices, merged the separate quad files into a single lattice and then projected the complete file into NJ State Plane coordinate system. The horizontal and vertical units were converted to US feet. The merged lattice was clipped to the watershed boundary with a buffer of 67 feet to allow for grid cell overlap and to eliminate gaps between watersheds when appended.
Time Period of Content:
Time Period Information:
Range of Dates/Times:
Beginning Date: 9/2000
Beginning Time: Unknown
Ending Date: 6/2002
Ending Time: Unknown
Currentness Reference: ground condition
Status:
Progress: Complete
Maintenance and Update Frequency: None planned
Spatial Domain:
Bounding Coordinates:
West Bounding Coordinate: -74.737181
East Bounding Coordinate: -74.343265
North Bounding Coordinate: 41.337867
South Bounding Coordinate: 40.990466
Keywords:
Theme:
Theme Keyword Thesaurus: None
Theme Keyword: Elevation
Theme Keyword: Digital Elevation Model
Theme Keyword: Digital Terrain Model
Theme Keyword: Lattice
Theme Keyword: DEM
Theme Keyword: Watershed Management Area
Theme Keyword: Ten meter
Theme Keyword: NJDEP
Place:
Place Keyword Thesaurus: None
Place Keyword: Wallkill Watershed Management Area
Place Keyword: WMA 2
Place Keyword: New Jersey
Place Keyword: USA
Access Constraints: None.
Use Constraints:
Data Distribution Agreement (NJDEP)
Agrees to abide by the terms and conditions of the following:
I. Description of Data to be Provided
The data provided herein are distributed subject to the following conditions and restriction .
Subject Data Layers
For all data contained herein, (NJDEP) makes no representations of any kind, including, but not limited to, the warranties of merchantability or fitness for a particular use, nor are any such warranties to be implied with respect to the digital data layers furnished hereunder. NJDEP assumes no responsibility to maintain them in any manner or form.
II. Terms of Agreement
1. Digital data received from the NJDEP are to be used solely for internal purposes in the conduct of daily affairs.
2. The data are provided, as is, without warranty of any kind and the user is responsible for understanding the accuracy limitations of all digital data layers provided herein, as documented in the accompanying Data Dictionary and Readme files. Any reproduction or manipulation of the above data must ensure that the coordinate reference system remains intact.
3. Digital data received from the NJDEP may not be reproduced or redistributed for use by anyone without first obtaining written permission from the NJDEP. This clause is not intended to restrict distribution of printed mapped information produced from the digital data.
4. Any maps, publications, reports, or other documents produced as a result of this project that utilize NJDEP digital data will credit the NJDEP Geographic Information System (GIS) as the source of the data with the following credit/disclaimer: This (map/publication/report) was developed using New Jersey Department of Environmental Protection Geographic Information System digital data, but this secondary product has not been verified by NJDEP and is not state-authorized.
5. Users shall require any independent contractor, hired to undertake work that will utilize digital data obtained from the NJDEP, to agree not to use, reproduce, or redistribute NJDEP GIS data for any purpose other than the specified contractual work. All copies of NJDEP GIS data utilized by an independent contractor will be required to be returned to the original user at the close of such contractual work. Users hereby agree to abide by the use and reproduction conditions specified above and agree to hold any independent contractor to the same terms. By using data provided herein, the user acknowledges that terms and conditions have been read and that the user is bound by these criteria.
Browse Graphic:
Data Set Credit: Original source 1:24,000 (10-meter) DEM's were purchased from USGS. This grid data set was produced by the NJ Department of Environmental Protection, Bureau of Geographic Information and Analysis.
Native Data Set Environment: ArcInfo 8.1.2
Data Quality Information
Section Index
Attribute Accuracy:
Attribute Accuracy Report:
The accuracy of a DEM is dependent upon the level of detail of the source and the grid spacing used to sample that source. The primary limiting factor for the level of detail of the source is the scale of the source materials. The original source data, supplied at 10-meter x 10-meter cell size by USGS, was edgematched and hydrologically enhanced. The proper selection of grid spacing determines the level of content that may be extracted from a given source during digitization.
Logical Consistency Report:
The fidelity of the relationships encoded in the data structure of the DEM are automatically verified using a USGS software program upon completion of the data production cycle. The test verifies full compliance to the DEM specification.
Completeness Report:
The DEM is visually inspected for completeness on a DEM view and edit system for the purpose of performing a final quality control and if necessary edit of the DEM. The physical format of each digital elevation model is validated for content completeness and logical consistency during production quality control and prior to archiving in the National Digital Cartographic Data Base. Due to the variable orientation of the quadrilateral in relation to the Universal Transverse Mercator (UTM) projection grid, profiles that pass within the bounds of the DEM quadrilateral, may be void of elevation grid points, and are not represented in the DEM. This condition occurs infrequently and is always the first or last profile of the dataset.
Level 2 DEM: Level 2 DEM's may contain void areas due to interruptions to contours in the source graphic or DLG. Void area elevation grid posts are assigned the value of -32,767. In addition, suspect elevation areas may exist in the DEM but are not specifically identified. Suspect areas can be located on the source graphic as a "disturbed surface, " symbolized by contours overprinted with photorevised or other surface patterns.
Positional Accuracy:
Horizontal Positional Accuracy:
Horizontal Positional Accuracy Report:
The horizontal accuracy of the DEM is expressed as an estimated root mean square error (RMSE). The estimate of the RMSE is based upon horizontal accuracy tests of the DEM source materials which are selected as equal to or less than intended horizontal RMSE error of the DEM. The testing of horizontal accuracy of the source materials is accomplished by comparing the planimetric (X and Y) coordinates of well-defined ground points with the coordinates of the same points as determined from a source of higher accuracy.
Vertical Positional Accuracy:
Vertical Positional Accuracy Report:
The vertical RMSE statistic is used to describe the vertical accuracy of a DEM, encompassing both random and systematic errors introduced during production of the data. The RMSE is encoded in element number 5 of record C of the DEM. Accuracy is computed by a comparison of linear interpolated elevations in the DEM with corresponding known elevations. Test points are well distributed, representative of the terrain, and have true elevations with accuracy's well within the DEM accuracy criteria. Acceptable test points include, in order of preference: field control, aerotriangulated test points, spot elevations, or points on contours from existing source maps with appropriate contour interval. A minimum of 28 test points per DEM is required to compute the RMSE, which is composed of a single test using 20 interior points and 8 edge points. Edge points are those which are located along, at, or near the quadrangle neatlines and are deemed by the editor to be useful to evaluating the accuracy of the edge of the DEM. Collection of test point data and comparison of the DEM with the quadrangle hypsography are conducted by the quality control units within the USGS.
There are three types of DEM vertical errors; blunder, systematic and random. These errors are reduced in magnitude by editing but cannot be completely eliminated. Blunder errors are those errors of major proportions and are easily identified and removed during interactive editing. Systematic errors are those errors that follow some fixed pattern and are introduced by data collection procedures and systems. These error artifacts include: vertical elevation shifts, misinterpretation of terrain surface due to trees, buildings and shadows, and fictitious ridges, tops, benches or striations. Random errors result from unknown or accidental causes.
DEM's are edited to correctly depict elevation surfaces that correspond to water bodies of specified size.
Level 1 DEM: A RMSE of 7-meters or less is the desired accuracy standard. A RMSE of 15-meters is the maximum permitted. A 7.5-minute DEM at this level has an absolute elevation error tolerance of 50 meters (approximately three times the 15-meter RMSE) for blunder errors for any grid node when compared to the true elevation. Any array of points in the DEM can not encompass more than 49 contiguous elevations in error by more than 21 meters (three times the 7-meter RMSE). Systematic errors that are within stated accuracy standards are tolerated.
Level 2 DEM: A vertical RMSE of one-half of the contour interval, determined by the source map, is the maximum permitted. Systematic errors may not exceed one contour interval, determined by the source map, is the maximum permitted. Systematic errors may not exceed one contour interval specified by the source graphic. Level 2 DEMs have been processed or smoothed for consistency and edited to remove identifiable systematic errors.
Lineage:
Source Information:
Source Citation:
Citation Information:
Originator: USGS
Publication Date: Unknown
Title: USGS 10-meter DEMs
Geospatial Data Presentation Form: raster digital data
Publication Information:
Publication Place: Sioux Falls, SD
Publisher: USGS
Online Linkage: http://gisdata.usgs.net/ned/About.htm
Source Scale Denominator: 24000
Type of Source Media: CD-ROM
Source Time Period of Content:
Time Period Information:
Single Date/Time:
Calendar Date: Unknown
Time of Day: Unknown
Source Currentness Reference: ground condition
Source Citation Abbreviation: USGS
Source Contribution: DEMs converted to raster and projected to NJ state plane coordinate system.
Process Step:
Process Description:
The production procedures, instrumentation, hardware and software used in the collection of standard U. S. Geological Survey (USGS) Digital Elevation Models (DEM's) vary depending on systems used at the contractor, cooperator or National Mapping Division (NMD) production sites. This process step describes, in general, the process used in the production of standard USGS DEM datasets.
Level 1 DEM: Level 1 DEM's are acquired photogrammetrically by manual profiling or image correlation techniques from National Aerial Photography Program (NAPP) or equivalent source photographs. Level 1 30-minute DEM's may be derived or resampled from level 1 7.5- minute DEM's.
Level 2 DEM: Level 2 DEM's are produced by converting 1:24,000-scale and 1:100,000-scale hypsography digital line graph (DLG) data to DEM format or the DEM's are generated from vector data derived from scanned raster files of USGS 1:24,000-scale or 1:100,000-scale map series contour separates.
Level 3 DEM: Level 3 DEM's are created from DLG data that has been vertically integrated with all categories of hypsography, hydrography, ridge line, break line, drain files and all vertical and horizontal control networks. The production of level 3 DEMs requires a system of logic incorporated into the software interpolation algorithms that clearly differentiates and correctly interpolates between the various types of terrain, data densities and data distribution.
Water body editing: DEM surface areas corresponding to water bodies are flattened and assigned map specified or estimated surface elevations. Water body areas are defined as ponds, lakes, and reservoirs that exceed 0.5 inches at map scale and double line drainage that exceeds 0.25 inches at map scale. Water body shorelines are derived either from a hypsographic DLG or by interactive delineation from 1:24,000-scale or 1:100,000-scale USGS map series.
Edge matching: DEM datasets within a project area (consisting of a number of adjacent files) are edge matched to assure terrain surface continuity between files. Edge matching is the process of correcting adjacent elevation values along common edges. The objective of edge matching is to create more accurate terrain representations by correcting the alignment of ridges and drains, and overall topographic shaping within an approximately 25-30 row or column grid post zone on both edges.
Quality control: DEM's are viewed on interactive editing systems to identify and correct blunder and systematic errors. DEM's are verified for physical format and logical consistency at the production centers and before archiving in the National Digital Cartographic Data Base (NDCDB) utilizing the Digital Elevation Model Verification System (DVS) software.
DEM Conversion to Grid lattice: The 10-meter DEM files were supplied to NJ DEP as individual dem files ( UTM- meters, NAD83) by USGS quadrangle. Each DEM was converted to a lattice. The DEMs were merged into one watershed management area wide grid and converted to a lattice with a z-factor of 3.2808 (ft/m) and FLOAT option. The appropriate WMA lattice was projected to NJ State Plane Coordinates with the BILINEAR option. This grid was then clipped by the appropriate watershed management area boundary (buffered by 67 feet) data set to produce the resulting WMA lattice. The WMA boundary had been buffered to allow for grid cell overlap when appending WMA grids. No further processing such as filling of sinks was done to the grid data set.
Process Date: 200204
Process Contact:
Contact Information:
Contact Person Primary:
Contact Person: Craig Coutros
Contact Organization: NJ Dept. of Environmental Protection, Bureau of Geographic Information and Analysis
Contact Position: GIS Specialist
Contact Address:
Address Type: mailing and physical address
Address: 401 East State Street, First Floor, PO Box 428
City: Trenton
State or Province: New Jersey
Postal Code: 08625-0428
Country: USA
Contact Voice Telephone: 609-292-0899
Contact Facsimile Telephone: 609-292-7900
Contact Electronic Mail Address: Craig.Coutros@dep.state.nj.us
Hours of Service: 8-4
Cloud Cover: 0
Spatial Data Organization Information
Section Index
Direct Spatial Reference Method: Raster
Raster Object Information:
Raster Object Type: Grid Cell
Row Count: 3854
Column Count: 3296
Vertical Count: 1
Spatial Reference Information
Section Index
Horizontal Coordinate System Definition:
Planar:
Grid Coordinate System:
Grid Coordinate System Name: State Plane Coordinate System 1983
State Plane Coordinate System:
SPCS Zone Identifier: 2900
Transverse Mercator:
Scale Factor at Central Meridian: 0.9999
Longitude of Central Meridian: -74.5
Latitude of Projection Origin: 38.833333
False Easting: 492125
False Northing: 0
Planar Coordinate Information:
Planar Coordinate Encoding Method: Coordinate Pair
Coordinate Representation:
Abscissa Resolution: 32.817469
Ordinate Resolution: 32.817469
Planar Distance Units: survey feet
Geodetic Model:
Horizontal Datum Name: North American Datum of 1983
Ellipsoid Name: Geodetic Reference System 80
Semi-major Axis: 6378137
Denominator of Flattening Ratio: 298.257222
Vertical Coordinate System Definition:
Altitude System Definition:
Altitude Datum Name: North American Vertical Datum of 1988
Altitude Distance Units: feet
Entity and Attribute Information
Section Index
Detailed Description:
Entity Type:
Entity Type Label: Elevation
Entity Type Definition: Elevation Value in feet
Entity Type Definition Source: USGS
Attribute:
Attribute Label: Pixel Value
Attribute Definition: Elevation in feet
Attribute Definition Source: USGS
Attribute Domain Values:
Range Domain:
Range Domain Minimum: 374.8555
Range Domain Maximum: 1809.7509
Attribute Units of Measure: feet
Distribution Information
Section Index
Distributor:
Contact Information:
Contact Organization Primary:
Contact Organization: NJDEP/OIRM/BGIA
Contact Address:
Address Type: mailing and physical address
Address: 401 East State Street, First Floor, PO Box 428
City: Trenton
State or Province: New Jersey
Postal Code: 08625-0428
Country: USA
Contact Voice Telephone: 609-984-2243
Contact Facsimile Telephone: 609-292-7900
Contact Instructions: Call 609-984-2243 with questions concerning only the acquisition/download of this data set. Call the metadata reference contact with questions concerning the data.
Resource Description: 10-meter Digital Elevation Grid for the Wallkill Watershed Management Area (WMA 2)
Distribution Liability: See "Use Constraints"
Standard Order Process:
Digital Form:
Digital Transfer Information:
Format Name: RASTER
Format Version Number: ArcGIS 8.1.2
File Decompression Technique: WinZip
Digital Transfer Option:
Online Option:
Computer Contact Information:
Fees: None
Ordering Instructions: None
Metadata Reference Information
Section Index
Metadata Date: 5/13/2002
Metadata Review Date:
Metadata Future Review Date:
Metadata Contact:
Contact Information:
Contact Person Primary:
Contact Person: Craig Coutros
Contact Organization: NJ Dept. of Environmental Protection, Bureau of Geographic Information and Analysis
Contact Position: GIS Specialist
Contact Address:
Address Type: mailing and physical address
Address: 401 East State Street, First Floor, PO Box 428
City: Trenton
State or Province: New Jersey
Postal Code: 08625-0428
Country: USA
Contact Voice Telephone: 609-292-0899
Contact Facsimile Telephone: 609-292-7900
Contact Electronic Mail Address: Craig.Coutros@dep.state.nj.us
Hours of Service: 8-4
Metadata Standard Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata Standard Version: FGDC-STD-001-1998
Metadata Time Convention: local time
SMMSMetadata report generated 2002/10/10