17.0 Feature Attribute Encoding Guide
For Field Units who have submitted a feature file to the Office of Coast Survey, the following S-57 attribution must be used per the legend below. In addition to S-57 attribute standards are NOAA extended attributes.
(m) | Mandatory |
(c) | Conditional |
(r) | Restricted |
17.1 Assigned/New/Update/Disproved Features
The following rules are applicable to all Assigned (i.e. asgnmt = Assigned), New, Update, and Disproved features (i.e. descrp = New, Update, or Delete).
Attribute | Description | |
descrp (m) | Description (m) | Portrays the field charting action. |
New (m) | New features or new position. | |
Update (m) | Modification to attribution, geometry, and/or feature object class. Exception: change of geometry for line and area. | |
Delete (m) | Disprovals or erroneous features. | |
Retain (m) | Addressed items that are represented properly on the chart. Include a remark for information purposes as necessary. | |
Not Addressed (m) | For assigned items that were not addressed, include remark describing why the feature was not addressed. |
17.2 Disproved/Retained/Not Addressed Features
Disproved, Retained, and Not Addressed features (i.e. descrp = Delete, Retain, or Not Addressed) will always maintain their original SORDAT and SORIND and other associated attribution. Remarks may be used as-needed. If the feature is recommended for deletion (i.e. it is Disproved) based on criteria or reasoning other than what is required in Section 7.5 in Features, Remarks should be provided.
Attribute | Description | |
remrks (c) | Remarks (c) | Provides additional information about features that is not captured elsewhere in digital data (e.g. S-57 attribution) |
17.3 New/Updated Features
The following rules are applicable to all New and Update features (i.e. descrp = New or Update).
Attribute | Description | |
SORIND (m) | Source Indication (m) | Information about the source of the object |
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SORDAT (m) | Source Date (m) | The last day of survey acquisition formatted as YYYYMMDD |
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OBJNAM (c) | Object Name (c) | Include for named features that are retained or relocated |
remrks (c) | Remarks (c) | Provides additional information about features that is not captured elsewhere in digital data (e.g. S-57 attribution) |
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sftype (c) | Special Feature Type (c) | Indicates a feature with special designation |
ATON (c) | ATON investigations | |
DTON (c) | Dangers to Navigation | |
Maritime Boundary (c) | Maritime Boundary investigations | |
Lidar investigation (c) | Lidar investigations | |
Unverified Charted Feature (c) | Unverified Charted Feature | |
images (c) | Images (c) | Images associated with a feature (e.g. MBES or SSS screen captures, or digital photos) |
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asgnmt (c) | Assignment Flag (c) | Indicates assignment status of items delivered to the field by the OCS Project Manager and/or COR |
Unassigned (c) | Not Assigned | |
Assigned (c) | Assigned | |
For Info Only (c) | For information only | |
invreq (c) | Investigation Requirements (c) | Specific investigation requirements defined by the OCS Project Manager and/or COR |
New vs Update Encoding
The following are typical examples of how to encode New vs Update for features.
- Charted point feature is found in new position via multibeam, lidar, vessel-mounted laser scanning, or any remote sensing system capable of generating a georeferenced point cloud at a resolution able to support creating a gridded product at 1/2 the size of the features claimed to be detected by the survey:
- descrp = Delete for the charted feature.
- descrp = New for surveyed feature (derived from grid or point cloud).
- Charted point feature is found via visual observation or handheld laser range finder, within 10 meters of the charted feature:
- descrp = Update (populate surveyed height/depth of feature, not position; update other attribution accordingly, if different).
- Charted point feature is found via visual observation or handheld laser range finder, greater than 10 meters from the charted feature:
- descrp = Delete for charted feature.
- descrp = New for surveyed feature (derived from visual observation or handheld laser range finder).
- Charted line or area feature geometry has changed, and less than half the node coordinates are affected:
- descrp = Update; then manually edit the geometry.
- If the new area extents border the edge of bathymetry, instead of manually editing the geometry, the hydrographer may use recomd = edit the geometry to extents of bathymetry.
- Charted line or area feature geometry has changed, and more than half the node coordinates are affected:
- descrp = Delete for charted feature.
- descrp = New for surveyed feature.
- If the new area extents border the edge of bathymetry, instead of manually creating new geometry, the hydrographer may use recomd = edit the geometry to extents of bathymetry.
17.4 NOAA Discretionary Attribution
The following is a list of additional NOAA Extended Attributes that may be used by Field Units, but must be removed prior to submitting to the Office of Coast Survey.
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17.5 Other Common Features by Acronym
The following table includes mandatory and conditional S-57 Attribution requirements for the most common features found in a feature file as well as some specific guidance in the note sections for each feature class. If a Field Unit has a question regarding attribution for a feature class not listed, contact the OCS Project Manager and/or COR for guidance.
Note: The following is only for New and Updated Features (descrp = New or Update). Features that are disproved, retained or not addressed will maintain the original S-57 attribution.
Obstructions (OBSTRN)
All new/updated obstructions must have a VALSOU or a HEIGHT with the following exceptions:
- If it is too dangerous to obtain the least depth/height.
- For line/area objects where least depth cannot be determined.
- If the object is a Foul Ground or Foul Area.
The attribution logic is shown in the table below.
Obstruction (OBSTRN) | w/ VALSOU | w/ HEIGHT | w/o VALSOU and HEIGHT | CATOBS = Foul Area | CATOBS = Foul Ground |
VALSOU | (m) | (r) | (r) | (r) | (r) |
HEIGHT | (r) | (m) | (r) | (r) | (r) |
WATLEV* | (m) | Always Dry (WATLEV = 2) (m) | (c) | (c) | Always underwater/submerged (WATLEV = 3) (m) |
QUASOU* | (m) | (r) | (r) | (r) | (r) |
TECSOU* | (m) | (r) | (r) | (r) | (r) |
CATOBS | (c) | (c) | (c) | Foul Area (CATOBS = 6) (m) | Foul Ground (CATOBS = 7) (m) |
NATSUR | (c) | (c) | (c) | (c) | (c) |
images | (m) | (m) | (m) | (r) | (r) |
* See below attribution for WATLEV, QUASOU, and TECSOU
Uncharted obstructions may be identified just outside of the boundaries of the permitted features shown below. In such circumstances, the permitted feature must not be submitted with edited geometry (i.e. descrp = Update) in order to encompass the obstructions. The uncharted obstructions, if warranted, must be submitted as new obstructions (i.e. descrp = New).
- Dumping ground (DMPGRD)
- Fish haven (OBSTRN with CATOBS = 5)
Wellhead Obstructions (CATOBS = 2) Guidance
- If a wellhead is found and considered a danger to navigation, develop the feature, submit it as a DTON, and include it in the feature file.
- If a wellhead is found and merits individual cartographic representation, develop the feature and submit it in the feature file. Note: if the wellhead is deeper than 20 m then it is unlikely to merit individual cartographic representation.
- If wellhead is found and does not merit cartographic representation, do not investigate it as a feature. Include it in the feature file with “descrp = delete” and “remrks=wellhead addressed as represented in the surface”.
- If the charted wellhead is not found, in cases where 100% side scan sonar with concurrent multibeam is used as the primary coverage technique, a 50 m disproval search radius is required. Include in the feature file with descrp = delete.
Rocks (UWTROC)
Rocks appropriately represented in the submitted grid(s) must not be included in the feature file, except for named rocks, which must be included in the feature file. New/updated rocks surveyed outside of the grid(s) must be included in the feature file and have a VALSOU, unless the feature is too dangerous to obtain the least depth. Note, baring rocks do not use HEIGHT; instead they become islets. See WATLEV attribution for guidance.
If several assigned rocks are found to be part of an inshore rocky area, the hydrographer may elect to delineate the area as Foul Area (OBSTRN area with CATOBS = “6” Foul Area) and forgo investigating each individual rock (i.e., descrp=Not addressed, remrks= “Rock is part of foul area”). Pending safe conditions, the hydrographer must address any rocks that they feel are navigationally significant within the foul area.
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(m) |
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* See below attribution for WATLEV, QUASOU, and TECSOU
Wrecks (WRECKS)
All new/updated wrecks must have a VALSOU or HEIGHT unless the feature is too dangerous to obtain the least depth.
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* See below attribution for WATLEV, QUASOU, and TECSOU.
Additional Features
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COALNE (Coastline) | CATCOA (m) | Category of Coastline |
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LNDELV (Land elevation) | ELEVAT (m) | Elevation |
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MORFAC (Mooring/Warping facility) | CATMOR (m) | Category of mooring/warping facility |
BOYSHP (c) | Buoy shape | |
COLOUR (c) | Color | |
COLPAT (c) | Color pattern | |
CONDTN (c) | Condition | |
NATCON (c) | Nature of construction | |
STATUS (c) | Status | |
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PILPNT (Pile) | CATPLE (c) | Category of pile |
CONDTN (c) | Condition | |
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CATPIP (c) | Category of pipeline/pipe |
SOUNDG (Sounding) | TECSOU (m) | Technique of sounding measurement |
QUASOU (m) | Quality of sounding measurement | |
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NATSUR* (m) | Nature of Surface |
NATQUA* (c) | Nature of Surface - Qualifying Terms | |
COLOUR* (c) | Color | |
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NATSUR (m) | Nature of Surface |
WATLEV (m) | Water Level Effect - reefs, ledges, and rocky seabed areas | |
NATQUA (c) | Nature of Surface = Qualifying Terms | |
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SLCONS (Shoreline construction) | CATSLC (m) | Category of shoreline construction |
CONDTN (c) | Condition | |
WATLEV (c) | Water level effect |
17.6 Attribution Guidance
TECSOU and QUASOU Attribution
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* If point cloud data was obtained over a feature but the least depth of the feature was not captured, QUASOU can be attributed as '1' Depth Known.
WATLEV Attribution
Rocks, obstructions and wrecks may be classified as always underwater, awash, or covers and uncovers. Obstructions and wrecks may also be classified as always dry.
- A bare rock extends more than 0.1 meter above the shoreline plane of reference (SPOR), typically Mean High Water (MHW).
- A rock, which covers and uncovers is exposed at some stage of tide from 0.1 meter above MHW to 0.1 meter above chart datum.
- An awash rock lies less than 0.1 meter above chart datum to 0.1 meter below the chart datum.
- A submerged (always underwater) rock is deeper than 0.1 meter from the chart datum.
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- Vertical coordinate system is positive up for elevations and positive down for depths.
* A rock becomes an islet at 0.1 meters above SPOR (e.g. MHW). LNDARE point or area objects are used to characterize islets. Elevation for islets is encoded using the object LNDELV, with attribute ELEVAT, and is shown relative to the SPOR.
** When the depth of an obstruction or wreck is greater than 0.1 meters above MHW, HEIGHT attribution is required rather than VALSOU. As with ELEVAT, heights are shown relative to SPOR (e.g., MHW).