Plotting Geodetic Marks

• Use the Go To Location on the menu to the left to zoom into the region and plot marks
• Right click on the map in your area of interest and select 'Place X'
  • You can change the radius used to plot marks under the Map Layers
    (15 mile max in Internet Explorer, 30 mile max other browsers)
• Zoom in to the region of interest
  • Click on the Map Layers section on the menu to the left
  • Select all of the types of marks to plot on the map
  • Click the "Find Marks" button

Clearing Geodetic Marks

1. Click on the Map Layers section on the menu to the left
2. Click the "Clear Marks" button

Viewing the Mark List

• To view the Mark List there must be marks plotted on the map
• Click on the View List button at the top of the menu to the left
• You can sort the mark list by any attribute when clicking on the headers of the table
• By clicking on the PIDs listed you can view the Datasheet

Control Mark Information

1. To view information about a control mark click on the marker on the map.
2. The following attributes are listed for each mark
   • PID – The PID of the mark with a hyperlink to the Datasheet
   • Name – The name of the mark
   • Control Type – The type of control the mark is plotted on the map
     **Read the Symbology section of Help for more information
   • Elev Source – Lists the source of the elevation
   • V Order – The Vertical Order of the bench mark
   • Pos Source – Lists the source of the position
   • HOrder – The Horizontal Order of the mark
   • Ellip Ht – The Ellipsoid Height of the mark if it has been GPSed
3. By viewing the Mark List you can view and sort the attributes of the markers. The Datasheet can be retrieved by clicking on the PID in the list.

Geodetic Marks

Symbol	Type	Description
	CORS Site	Continuously Operating Reference Station
	GPS Site	Any site that has an Ellipsoid height
	Classic Horizontal	Any mark with a Horizontal Source of [ADJUSTED or NO CHECK]

Symbol	Type	Description
	Leveled Height	Any mark with a Vertical Source of [ADJUSTED, ADJ UNCH, POSTED, READJUST, N HEIGHT, RESET, COMPUTER, GPSCONLV, LEVELING]
	Modeled Height	Any mark with a Vertical Source of [GPS OBS, VERTCON]
	Approximate Height	Any mark with a Vertical Source of [H LEVEL, VERT ANG, U HEIGHT]

Symbol	Type	Description
	GPS and Leveled Height	Fits criteria for both GPS Site and Leveled Height
	GPS and Modeled Height	Fits criteria for both GPS Site and Modeled Height
	GPS and Approximate Height	Fits criteria for both GPS Site and Approximate Height
	Classic Horizontal and Leveled Height	Fits criteria for both Classical Horizontal and Leveled Height
	Classic Horizontal and Modeled Height	Fits criteria for both Classical Horizontal and Modeled Height
	Classic Horizontal and Approximate Height	Fits criteria for both Classical Horizontal and Approximate Height

Clustered Marks

Symbol	Description
	Cluster of 2 to 9 Marks
	Cluster of 10 to 99 Marks
	Cluster of more than 100 Marks

Using the Go To Location Menu

1. Geographic Location – allows you to enter any place name, zip code, city or state to zoom to
2. Lat-Lon Location – allows you to enter a latitude and longitude in Degrees Minutes Seconds format
3. Dec Deg Location – Allows you to enter any Lat and Lon in decimal degrees to zoom to
4. PID – Allows the user to enter a PID and zoom to that location
5. CORS Site – Allows the user to enter a CORS site id to zoom to.

• Email : ngs.infocenter@noaa.gov
• Telephone: (301) 713-3242 ( Mon. – Fri., 9:00 a.m. – 4:30 p.m., EST )
• Fax: (301) 713-4172; or
• Postal Mail:
  Communications and Outreach Branch, NOAA, N/NGS12
  National Geodetic Survey, SSMC-3, #9202
  1315 East-West Highway
  Silver Spring, MD 20910-3282

1. What are the colored squares with numbers in them and what do the numbers mean?
   • The squares are clusters of marks in that area. The number is the number of marks in the area.
2. What does the 'Mark Center' button do exactly?
   • The Mark Center button places an X at the very center of the current map extent and performs a radius search base on the radius distance specified.
3. What does 'Modeled Height' mean?
   • Marks classified as Modeled Heights are marks that have either GPS OBS or VERTCON as their ELEV_SRCE. VERTCON marks are NGVD29 elevations converted to NAVD88 heights and GPS OBS heights use a geoid model to determine the orthometric height