Process Description:
The Riparian Tidelands Grid was updated for topological discrepancies, unnecessary features and additional attribute fields. Geometry errors consist of gaps between grids, overlapping grids, and vertex errors.
The following topological rules were created to find and fix erroneous geometry:
- Must not overlap
- Must not have gaps
A temporary field was created to find features with more than four vertices. Since the grids are squares, each features needs exactly 1 vertex for each corner. Removing overlapping vertices solved additional geometry errors.
A new attribute field, named Grid ID, was created based on the Y and X field to easily search for a specific grid. The Grid ID starts with the first three digits of the y coordinate followed by the first four digits of the x coordinate The x and y coordinate values are based on the the bottom left corner vertex and are in NJ state plane feet.
New attribute fields were created to aid in generalizing grids by themes. Grids were arranged into the following themes:
- Tidelands Region
- Tidelands Claim Status
The tidelands grids were split into regions based on the Tidelands regions map: https://www.nj.gov/dep/gis/digidownload/images/tidelands/tide_regions.gif. The TIDELANDS_REGION field was updated based on the region each grid intersected. The tidelands claim layer was used to assign a tidelands claim status for each grid. The field, Claim_Status, was assigned the attribute, claimed, if any grids intersected formally flowed tidal areas. Grids that did not intersect any such areas were assigned the attribute unclaimed.
An additional attribute field was created used to classify each grid based on a claim type. A claim type is a descriptor of claimed/unclaimed features in the grid which come from the Source Selection Maps. The claim types consist of:
- Tidally Flowed
- Openwater
- Time-Barred
- Time-Barred Dam
- Time-Barred Openwater
- Upland
The Source Selection Maps are a set of maps created based on the amalgamation of images and drawings outlining waterbodies that are currently and formerly flowed by the mean high tide of a natural waterway. The legislature passed a constitutional amendment requiring the state to stake its claims to formally tide flowed lands statewide by November 3rd 1982. Any maps officially adopted after November 3rd 1982 where not able to assert ownership of tidelands 40 years before the adoption date. Even though naturally waterways existed in historical sources beyond the 40-year period, these features are considered time-barred. In order to classify a claim type for each grid, each source selection map was visually reviewed for the different designations mentioned in the notes.
The date the grids were adopted by the Tidelands Resource Council (TRC) are also tied to each grid.