20230125
10454000
1.0
FALSE
AerialPhoto2018
632499.999824
772499.999824
745000.000186
925000.000186
1
Projected
GCS_North_American_1983
Linear Unit: Foot_US (0.304801)
NAD_1983_StatePlane_New_York_East_FIPS_3101_Feet
<ProjectedCoordinateSystem xsi:type='typens:ProjectedCoordinateSystem' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xmlns:xs='http://www.w3.org/2001/XMLSchema' xmlns:typens='http://www.esri.com/schemas/ArcGIS/3.0.0'><WKT>PROJCS["NAD_1983_StatePlane_New_York_East_FIPS_3101_Feet",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",492125.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",-74.5],PARAMETER["Scale_Factor",0.9999],PARAMETER["Latitude_Of_Origin",38.83333333333334],UNIT["Foot_US",0.3048006096012192],AUTHORITY["EPSG",2260]]</WKT><XOrigin>-17954600</XOrigin><YOrigin>-46918100</YOrigin><XYScale>137255069.87923574</XYScale><ZOrigin>-100000</ZOrigin><ZScale>10000</ZScale><MOrigin>-100000</MOrigin><MScale>10000</MScale><XYTolerance>0.0032808333333333331</XYTolerance><ZTolerance>0.001</ZTolerance><MTolerance>0.001</MTolerance><HighPrecision>true</HighPrecision><WKID>102715</WKID><LatestWKID>2260</LatestWKID></ProjectedCoordinateSystem>
8
FALSE
None
4
AMD
TRUE
continuous
unsigned integer
4100
15000
1000
20
2048
20
75
0.01
10
600
300
Basic
1
NorthWest,Center,LockRaster,ByAttribute,Nadir,Viewpoint,Seamline,None
None,JPEG,LZ77,LERC
None
None,Basic,Base-Top Height,Top-Top Shadow Height,Base-Top Shadow Height,3D
-1
-1
0.8
1
NorthWest,Center,LockRaster,ByAttribute,Nadir,Viewpoint,Seamline,None
None,JPEG,LZ77,LERC
None,Basic,Full
NONE
<_docversion_ Sync="TRUE">10
Name,MinPS,MaxPS,LowPS,HighPS,Tag,GroupName,ProductName,CenterX,CenterY,ZOrder,Shape_Length,Shape_Area
64000
0.5
1280
withheld
20230217
15241100
20230217
15241100
Ilir Tota
Westchester County GIS
Software Architect
914-995-5605
914-813-4116
Westchester County GIS
148 Martine Ave, Room 214
White Plains
New York
10601
US
20230217
ArcGIS Metadata
1.0
Westchester County NY High Resolution Orthophotos, Spring 2018
2019-02-27
Westchester County GIS, White Plains and IIC Technologies, Inc.
Westchester County GIS
White Plains, New York
raster digital data
Westchester County GIS
2018 imagery in Westchester County
This dataset consists of 6-inch pixel resolution, four band orthoimages covering the entire Westchester County NY with a buffer of 1000 ft. An orthoimage is remotely sensed image data in which displacement of features in the image caused by terrain relief and sensor orientation have been mathematically removed. Orthoimagery combines the image characteristics of a photograph with the geometric qualities of a map. The digital imagery was captured on April 14 and April 26, 2018.
The data depicts geographic features on the surface of the earth. It was created to provide easily accessible geospatial data which is readily available to enhance the capability of Federal, State, and local emergency responders, as well as plan for homeland security efforts. A digital orthoimage is a geometrically accurate photographic record of landscape conditions at the time of the corresponding aerial photography. As such, High Resolution Orthoimagery is useful for a variety of applications, such as environmental monitoring, facility engineering/maintenance, city/county planning, property line review, etc. The digital orthoimage can be used alone or as a raster basemap for corresponding vector line mapping. The detailed focus of High Resolution Orthoimagery provides emergency responders critical information in determining the best evacuation routes, alternative routes and safe access to aid. High Resolution Orthoimagery assists law enforcement personnel in determining the best locations to place surveillance cameras in high-traffic urban areas and popular attractions. The data assists Federal, State and local emergency responders in planning for homeland security efforts.
Westchester County GIS
Sam Wear/Ilir Tota
Westchester County GIS
914-995-5605
914-813-4116
Westchester County GIS
148 Martine Ave, Room 214
White Plains
New York
10601
US
iat2@westchestergov.com
8:30am -4:30pm Eastern time
Orthophotos
Base map
Westchester County
High Resolution
New York
aerial photo
orthophoto
aerial photography
Imagery
image map
air photo
Base Maps
Earth Cover
Westchester
imageryBaseMapsEarthCover
ISO 19115 Topic Categories
aerial photo
orthophoto
aerial photography
Imagery
image map
air photo
Base Maps
Earth Cover
Westchester
imageryBaseMapsEarthCover
Orthophotos
Base map
Westchester County
High Resolution
New York
Version 6.2 (Build 9200) ; Esri ArcGIS 10.8.1.14362
true
-73.992345
-73.478471
41.371617
40.874228
1
-73.992345
-73.478471
41.371617
40.874228
All GeoTIFF tagged data and image file sizes are validated using commercial GIS software to ensure proper loading before being archived. This validation procedure ensures correct physical format and field values for tagged elements. Seamlines and tile edges are visually inspected. Seamlines mismatches are not corrected unless the overall displacement exceeds one meter. Logical consistency is implicit in the raster image data structure. Source imagery is cloud free.
Orthoimages are visually inspected for completeness to ensure that no gaps or image misplacements exist within and between adjacent images. These images are derived by mosaicking multiple images to ensure complete coverage. Source imagery is cloud free. Photography was flown during leaf-off in deciduous vegetation regions.
The design accuracy is estimated not to exceed ASPRS Standard Mapping and GIS Standards of 2 pixel tolerance. The estimated horizontal positional accuracy value for the dataset is less than or equal to 15cm. The horizontal positional accuracy and the assurance of that accuracy depend, in part, on the accuracy of the data inputs to the rectification process. The location of ground control and aerotriangulation points were evaluated on the Geotiff image and compared with their ground values in order to determine an overall accuracy for each test block of orthoimages within the project. After image coordinate measurement was completed for each block, an RMSE for the diagonal error was calculated for the orthoimages within the block. This value is an estimate of the horizontal accuracy of the tile expressed in meters. The relative accuracy is assembled by comparing rectified images generated from adjacent strips of imagery. The absolute accuracy is assessed by measuring the ground control points in the rectified image against the actual surveyed co-ordinate position. The testing is for overall accuracy.
SOURCES: 1. Source Imagery – UltraCAM Eagle, Originator: IIC Technologies, Inc. Digital Camera Imagery Control - Airborne GPS/IMU supplemented with ground control points, Aerotriangulation – Inpho Match-AT, Orthorectification – Inpho Ortho Vista, DEM Mosaic – Updated from County LiDAR data using Inpho DTMaster. The digital imagery mission was composed of a total of 2 lifts. Imagery (6-inch GSD) was obtained at an altitude of about 7,000 feet above ground level on 14 and 26 April 2018. The missions were flown with a UltraCAM Eagle digital camera with airborne GPS (ABGPS) and internal measurement unit (IMU). This imagery provides the data for the digital orthoimage. 2. GPS Ground Control - Horizontal and vertical control was used to establish positions and elevations for reference and correlation purposes and as input to the aerotriangulation process. Control consists of surveyed ground control for ground reference. A total of 42 photoidentifiable ground control points were collected. 3. Existing DEM - Existing LiDAR data from 2009 was used as the base and updated using Inpho DTMaster to meet DEM for orthophotos and supplemented with breaklines. 4. Airborne GPS/IMU Data, Originator: IIC Technologies, Inc. - Airborne GPS (ABGPS) and IMU data are collected with an onboard dual frequency GPS survey unit and a corresponding IMU system in combination with the digital imagery. The GPS data provides the position of the imagery at the time of capture while the IMU system records instantaneous changes in position and attitude of the sensor. The GPS/IMU, base station, and ground control processing are an important step towards the development of accurate orthoimages. PROCESSING STEPS at IIC Technologies, Inc. Keystone Aerial Surveys, Inc. - The following describes the digital production sequence. 1. The raw (Level-0) data and associated GPS and IMU data for each mission is downloaded from the hard drives and checked to confirm that no files have been corrupted and that all data can be successfully downloaded. 2. The GPS and IMU data are post-processed along with the base station data to produce a precise position and attitude stream for each line of imagery. Post processing uses the high frequency readouts of the IMU to verify the GPS data and to provide instantaneous positioning of each line of imagery between GPS recordings. Likewise, the IMU attitude data is corrected for bias/drift and transformed to real world coordinates by using the GPS data. This process creates Level-1 rectified imagery which is an approximately geo-positioned image. 3. The production process uses aerial triangulation techniques to combine the short-term accuracy of the IMU with high global accuracy of GPS. In combination with the minimum required number of ground control points (GCPs), aerial triangulation delivers best fitting results on the ground. The extra information added to the system by automatic tie point measurements (APM) leads to very reliable orientation results where photogrammetric measurements serve to control IMU/GPS measurements and vice versa. 4. The results of the APM are run through a combined bundle adjustment process to further refine the measured image coordinates and the position and attitude values from IMU and GPS computed by IMU/GPS post processing. The bundle adjustment process equally compensates for systematic errors such as the misalignment between IMU and sensor axes, IMU/GPS drift, and the datum difference between IMU/GPS and ground control coordinate system. This results in a very accurate and precise determination of the parameters of exterior orientation which are later used for Orthorectification. 5. The orthorectification process uses the raw Level-0 data as the input imagery source to avoid repeated re-sampling of the imagery to yield the best possible image quality and accuracy. The raw Level-0 true color imagery is orthorectified to the DEM using the adjusted position and orientation results from the aerial triangulation phase. The orthorectified strip of imagery is called the Level-2 data. 6. The resulting images are then mosaicked and color balanced. 7. The final tiles are clipped out and the imagery is output in uncompressed GeoTIFF format with no overlap. 8. The completed four band digital orthophotos are checked for image quality. Minor artifacts are corrected using Adobe Photoshop in an interactive editing session. Digital tiles are assigned final names based on the tile grid maintained by Westchester County GIS.
2018-07-01
Aerial Imagery
3
2500
0.500000
2500
0.500000
1
1
0
632499.999824 745000.000186
632499.999824 925000.000186
772499.999824 925000.000186
772499.999824 745000.000186
702499.999824 835000.000186
EPSG
5.3(9.0.0)
Band_1
255.000000
10.000000
8
Band_2
255.000000
23.000000
8
Band_3
255.000000
20.000000
8
Band_4
255.000000
30.000000
8