Chart History and Data Quality Worksheet (Maritime Charting)

In the Chart History document, you record any feature interpretation or collection decisions that were made during the production of the chart. Anything out of the ordinary, such as collecting a feature with no guidance or explaining why information was omitted from one of the sources, would be included in this record. This is a place where you can document everything related to the production of the chart you are working on.

In addition to the Chart History document, there is a form called the DNC Data Quality Worksheet. This worksheet is used to record most of the data quality (metadata) information that needs to be maintained throughout the project. The information entered here is then used to create the Dqyarea.

Record the following information on the DNC Data Quality Worksheet:

Field name	Description
SOURCE_ID	Chart identifier, which is your specific chart number. For a foreign source, collect the integer portion of the foreign chart number.
Name	Chart name, which is the name from the title or, if you are working with a plan, the title of the plan. The name of the chart is usually found at the bottom right-hand corner. Enter the name exactly as it appears on the chart. Abbreviation of common terms is allowed. For a foreign source, collect the foreign country's two-letter abbreviation plus the full chart number followed by the chart title. Example: SP425A: Bahia de Alcudia. When a chart name is longer than 40 characters, enter the first 29 characters or slightly fewer to avoid breaking off in the middle of a word and append (see Note) to the end. Then enter the complete chart name in a notes.rat file. Some of the electronic navigation systems require unique names for the source charts in the DQYarea layer as no duplicates are allowed.
EDITION	Found in the lower left-hand corner of the chart. Verify that the edition number and date on the paper charts or supplied imagery match the edition number and date on the corresponding NGA ILI. Report any discrepancies to NGA. The edition number is especially critical for proper processing of Notice to Mariners updates.
SCALE	Found in the margin or in a corner of the chart. Leave off the 1: and enter the scale number only. For example, a scale of 1:250,000 would be entered as 250000.
REF_LAT	Found in the margin of the chart, usually with the scale. If it is not on the chart, check the ILI and use the mid-latitude from the geodesy report. If neither the chart nor the ILI contain any mention of reference latitude, use the center of the chart as the reference latitude. The reference latitude may be outside of the minimum bounding rectangle of the chart. The value should be collected to 6 decimal places as necessary.
ABS_HORIZ_ACC	This field should be marked as -9, unless such information is provided in a geodetic report with the ILI.
ABS_VERT_ACC	This field should be marked as -9, unless such information is provided in a geodetic report with the ILI.
DATUM	Hydrographic datum as shown on the chart (for example, Mean Lower Low Water). This information may also be abbreviated (for example, MLLW).
LINEAGE	Descriptive information that is found under the main title of the chart (for example, From South Korean charts in 1991). If some chart information is unclear or unknown, specify that the information is unclear or unknown (for example, First Edition Date unclear or unknown). If more than 100 characters are needed, enter the first 89 characters, or slightly fewer, to avoid breaking off in the middle of a word and append (see Note) to the end. Then enter the complete chart lineage in a notes.rat file.
SOURCE_INFO	Usually found under a designation such as SOUNDINGS IN METERS on the chart, and usually in black with a note next to it (for example, Soundings corrected for sound velocity). Also include the contour interval for topographic features if it is designated on the chart. The contour interval note will include the supplemental information. The sound velocity note is always first and the height and contour information last. If both the height and contour information cannot fit, attach each separately as a DQY notes.rat file.
COMP_DATE	The first edition date found on the top center of the chart (month, date, and year). The date is the first of the month unless the chart is the first edition; then the date matches the print date. A zero should precede all single-digit days or months. If the first edition date is unclear or unknown, collect as all zeros or all spaces.
PRINT_DATE	Chart edition date found in the lower left-hand corner of the chart.
CONTROL POINT COORDINATES	These are the control points used to georeference the chart. These coordinates can be stored by exporting the coordinates during the georeferencing process.