NJDEP 1977 Tidal Wetlands Basemaps
NJ Office of Information Technology (NJOIT), Office of Geographic Information Systems (OGIS)
This Web Map Service publishes the series of chronopaque photo-basemaps known as the “1977 Tidelands Basemaps.” The maps were scanned and georeferenced using the NJDEP Tidelands Grid vector data layer as the reference data set. Cropped versions of geo-referenced images are made available in this WMS. The WMS was created to provide a geo-referenced digital version of the 1977 Tidelands Basemaps for use in Geographic Information Systems and applications.
The photo-basemaps were originally produced to support the “Tidelands Act” (N.J.S.A. 12:3). The original basemaps were mylar photo-images at a scale of 1:2400 (1 inch = 200 feet), and were the base on which the state’s riparian land holdings were mapped. For the purposes of the act, riparian lands are defined as all areas that are now or formerly flowed at mean high tide by a natural waterway. The Tidelands Act set 1977 as the base year for determining the holdings, requiring the creation of the 1977 photo-basemap series. The actual riparian delineations were made on clear overlays affixed to these basemaps. These delineations are not imbedded in the photo-images, but exist as a separate vector data set idenified as the “Tidelands Claim Line”. Although identified as the 1977 Tidelands Basemaps, the aerial photographs used to generate the basemaps were actually taken over the course of two years, 1977 and 1978.
Mylar photo-basemaps were scanned at 300 dpi on an Oce TC4 Wide Format Color Scanner. Images were captured in uncompresssed tif format using a default contrast setting. A complete digital archive was created, consisting of approximately 1621 basemap images. Each image was named using the following convention: 1977_xxx_xxxxa.tif, where xxx_xxxx = the basemap number, and a = designation for archived image. Basemap numbers were assigned according to the New Jersey State Plane Coordinate System NAD27, in Feet, included at the lower left extent of the image. The first three digits of the map number are the first three digits of the northing (y-coordinate) value. The following four digits of the map number are the first four digits the easting (x-coordinate) value. Note that while the basemap and image numbers retain the NAD27 values, these scanned images are referenced in New Jersey State Plane Feet, NAD83.
Horizontal Position Accuracy
Scanned basemaps were georeferenced matching the four corners of the embedded reference grid within the image to the tidegrid vector digital data published by NJDEP. All efforts were made to keep georeferencing residuals below four (4) feet. In some cases it was not possible to meet this tolerance due to such issues as: lack of sufficient contrast in the image to clearly determine grid intersections, poorly embedded grid coordinates, stretch/skew of 40+ year old originals. Georeference points were set in the following order for all images: NW, SE, NE, SW.Reprocessing of imagery in order to publish as a WMS may have a slight impact on spatial accuracy of features.
Acknowledgement of the data set provider, NJDEP, and the WMS publisher, NJ Office of Information Technology (NJOIT), Office of Geographic Information Systems (OGIS), would be appreciated for maps, data or other products derived from this Web Map Service. The following language applies to the digital data, originated by NJDEP 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.
This map 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
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