Alternative Text Description for 2 ft. Contours (CDM)

TABLE OF CONTENTS

MAP OVERVIEW

This map displays 2-foot elevation contours for Duval County, Florida, derived from a digital terrain model created for the Florida Division of Emergency Management. The contours represent lines of equal elevation at 2-foot vertical intervals across the landscape. The map shows the topographic variation of the terrain, with contour lines revealing elevation changes throughout the Jacksonville metropolitan area and surrounding regions.

GEOGRAPHIC CONTEXT

The map covers Duval County, Florida, with the city of Jacksonville prominently labeled near the center of the mapped area. The geographic extent includes Fernandina Beach along the northeastern coastline, Hilliard to the northwest, Callahan in the central-western portion, and Bryceville to the west. Orange Park appears in the southern portion of the map, with Middleburg visible in the southwestern area. The Nassau Wildlife Management Area and Four Creeks Wildlife Management Area are labeled in the northern section, while Jennings Forest Wildlife Management Area appears in the southwest. Ponte Vedra and Jacksonville Beach are visible along the eastern coastal edge. The St. Johns River is evident as a major waterway running through the county. Green Cove Springs is labeled near the southern boundary.

KEY INSIGHTS

The contour patterns reveal that the majority of Duval County features relatively low-lying, gently sloping terrain with subtle elevation changes, typical of Florida's coastal plain topography. The high density of contour lines throughout the brown-shaded area indicates continuous terrain elevation data coverage across most of the county. Notable interruptions in the contour pattern appear along major waterways, particularly the St. Johns River and its tributaries, as well as along the Atlantic coastline, where these water features create natural breaks in the elevation surface. The western portions of the county show more concentrated contour patterns in some areas, suggesting slightly more varied topography compared to the flatter coastal zones. No dramatic elevation changes or mountainous terrain are present, consistent with the region's coastal plain geography.

VISUAL ELEMENTS

2 ft. Contours (CDM)

This layer represents elevation contours at 2-foot vertical intervals derived from LiDAR-based terrain modeling.

Contour Lines (olive/tan colored area)

Appearance:

The contours appear as a solid olive-tan or khaki-colored fill covering most of the mapped area, with numerous small white gaps distributed throughout representing the individual contour line spacing and water features.

Distribution:

Contour coverage extends across the majority of Duval County, from the western boundary eastward to the Atlantic coast, and from the northern county line south to the county's southern extent.

Notable locations:

Dense contour coverage is present around Jacksonville, throughout the central and western portions of the county, and in areas between major water features. The contours create a continuous surface across terrestrial areas.

Spatial patterns:

The contour pattern shows relatively uniform distribution across upland areas with regular interruptions along waterways. The St. Johns River creates a prominent meandering gap through the center of the county. Smaller waterways and coastal features create additional linear gaps in the contour pattern. The eastern coastal areas show irregular contour edges along the Atlantic shoreline and associated tidal waterways.

Water Bodies and Gaps

Appearance:

Water features appear as white or light gray gaps within the olive-tan contour coverage.

Distribution:

Major water gaps follow the St. Johns River and its tributaries, with additional gaps along coastal areas, creeks, and inland water bodies.

Notable locations:

The St. Johns River system creates the most prominent water feature pattern, with significant gaps near Jacksonville, extending both north and south. Coastal areas near Fernandina Beach, Jacksonville Beach, and Ponte Vedra show irregular water body patterns associated with tidal inlets and marshes.

Spatial patterns:

Linear and dendritic patterns follow natural drainage networks, while irregular coastal patterns reflect tidal environments and barrier island geography.

SYMBOL GUIDE

ADDITIONAL INFORMATION

This map is part of a comprehensive digital terrain model that includes multiple elevation products. While 2-foot contours meet National Map Accuracy Standards for mapping applications, the source dataset also includes 1-foot contours intended for visualization purposes. The contours were generated from a gridded digital elevation model derived from LiDAR data. The underlying terrain model is hydrologically corrected, meaning breaklines were captured along water features, roads, and other terrain features to ensure accurate representation of the landscape. At this map scale, individual contour lines are not visible as separate features; instead, they appear as a continuous coverage area. Water bodies, shorelines, and major hydrographic features appear as gaps in the contour coverage.

DATA CONTEXT

Data Source:

The data originates from a LiDAR-based digital terrain model created for the Florida Division of Emergency Management's Project Management and Technical Services for Mapping within Coastal Florida. The terrain model was developed from LiDAR masspoints with bare earth vertical accuracy of at least 0.3-feet root mean square error (RMSE) in open unobscured areas. Breakline features including water bodies, streams, shorelines, roads, and terrain features were captured to create a hydrologically correct digital terrain model. The source layer name is TOPO2FT_CDM.

Definition Query:

No definition query or filter criteria was specified for this map view.

Scale Information:

The map displays county-level coverage appropriate for regional planning and visualization. Individual 2-foot contour lines are not distinguishable at this scale; the display shows the overall extent of contour coverage.

Coordinate System:

NAD_1983_HARN_Florida_GDL_Albers (WKID 3087)

Time Period of Content:

The time period of data collection is not specified in the provided information.

Limitations:

The 2-foot contours are designed to meet National Map Accuracy Standards but may have limitations in areas of dense vegetation, urban development, or other conditions that affect LiDAR data collection. Low confidence areas may exist where data quality is reduced. Water bodies and coastal areas do not contain contour data as these represent non-terrain surfaces.

Map Coverage:

The map covers the entirety of Duval County, Florida, extending from the Atlantic coast in the east to the western county boundary, and from Nassau County in the north to Clay County in the south. Portions of neighboring counties and geographic features are visible for spatial context.

The alternative text description of this map was AI-generated and may contain inaccuracies.