| snippet:
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The DTM was created to support the development and maintenance of the St. Johns County Countywide Digital Contour Mapping Project. The project includes 6-inch color and IR countywide imagery. Breaklines improve the digital elevation model in areas where the point density is insufficient. |
| summary:
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The DTM was created to support the development and maintenance of the St. Johns County Countywide Digital Contour Mapping Project. The project includes 6-inch color and IR countywide imagery. Breaklines improve the digital elevation model in areas where the point density is insufficient. |
| extent:
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[[-81.6694593894904,29.6140585123773],[-81.212348195059,30.2608625716606]] |
| accessInformation:
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Data content is created and/or maintained by the St. Johns County GIS Division and Woolpert, Inc. |
| thumbnail:
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thumbnail/thumbnail.png |
| maxScale:
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1.7976931348623157E308 |
| typeKeywords:
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["Data","Service","Map Service","ArcGIS Server"] |
| description:
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<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>This data set is one component of a digital terrain model (DTM) for St. Johns County. The dataset is comprised of mass points, 2-D and 3-D breakline features, 1-foot and 2-foot contours, ground control, vertical test points, and a footprint of the data set, in the ESRI ArcGIS File Geodatabase format. In accordance with the counties specifications, the following breakline features are contained within the database: closed water bodies (lakes, reservoirs, etc) as 3-D polygons; linear hydrographic features (streams, shorelines, canals, swales, embankments, etc) as 3-D breaklines; coastal shorelines as 3-D linear features; edge of pavement road features as 3-D breaklines; soft features (ridges, valleys, etc.) as 3-D breaklines; island features as 3-D polygons; concretedam, culvert, footprint, lowconfidence, lowconfidenceanno, overpass, pipe, roadcenterlineoverbridge and swamppoint as 2-D features. Contours were generated from LiDAR ground class and breaklines and meet National Map Accuracy Standards. The LiDAR masspoints are delivered in the LAS file format based on the Florida statewide 5,000' by 5,000' grid. Breakline features were captured to develop a hydrologically correct DTM. The GEOID model used to reduce satellite derived elevations to orthometric height is GEOID12A. The coastalshoreline has a constant value of -0.6’ that was statistically derived from the LiDAR point cloud collected within the 2-hour window of MLL tide. 2008 Hydrographic and soft features were used to supplement the 2019 breaklines in Low Confidence areas.</SPAN></P></DIV></DIV></DIV> |
| licenseInfo:
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<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>Information from the St. Johns County Geographic Information System is provided for general reference purposes only and is not to be construed as a survey or legal document. Errors from non-coincidence of features from different sources may be present. The St. Johns County Geographic Information System makes every reasonable effort to ensure that the information provided herein is current and accurate. However, St. Johns County provides no warranties, expressed or implied, concerning the accuracy, completeness, reliability, or suitability of this data for any particular use or purpose. St. Johns County assumes no liability whatsoever associated with the use or misuse of such data.</SPAN></P></DIV></DIV></DIV> |
| catalogPath:
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|
| title:
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Elevation Contours 2019 |
| type:
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Map Service |
| url:
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|
| tags:
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["Terrain","Florida","United States","Contours","St. Johns County"] |
| culture:
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en-US |
| name:
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Elevation_Contours_2019 |
| guid:
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B47D0B3C-F0CC-4D2F-A25A-DBA533AF11CC |
| minScale:
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0 |
| spatialReference:
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WGS_1984_Web_Mercator_Auxiliary_Sphere |