2023 Aerial Imagery & Elevation

Statewide, 3 inch, 4 band orthoimagery AND statewide Quality Level 1 lidar (minimum of 15 points per square meter inland a minimum of 20 points per square meter along the coast) was collected in the spring of 2023. The project was managed by the CT State GIS Office with the Aerial Imagery Acquisition Workgroup.  See Funding and Project Management below for more information.

imagery icon

2023 Aerial Imagery

VIEW

CONNECT

DOWNLOAD

Aerial Imagery Viewer

The 2023 imagery is part of the online, interactive viewer that contains all of Connecticut's statewide, digital aerial imagery.
> Aerial Imagery Viewer Help

Image Services

for advanced users
On the Map and Image Services page, look for Imagery-Spring Statewide and then 2023 Spring 4 band, 3 inch. Both a dynamic service and tiled service are available.
> How to Connect to Services
> Service FAQs

Download

for GIS users
Download aerial imagery tiles as GeoTIFF tile, MrSID Generation 3, or MrSID Generation 4. Town mosaics are available as MrSID Generation 3 and MrSID Generation 4.

imagery icon

2023 Lidar Elevation

VIEW

CONNECT

DOWNLOAD

Elevation Viewer

The 2023 elevation is part of the online, interactive viewer that contains statewide elevation, hillshade, shaded relief, slope, and aspect.
> Elevation Viewer Help

Elevation Image Services

for advanced users
Go to the Map and Image Services page and look for Elevation Layers from 2023.
> How to Connect to Services
> Raster Processing Templates: Accessing and Applying for Elevation
> Services FAQ

Download

for GIS users
Download elevation as DEM GeoTIFF tile, geodatabase or shapefile contour files, or point cloud in LAZ format.

Building icon

2023 Buildings

DOWNLOAD

CONNECT

BLOCKS

Buildings BETA VERSION

for GIS users
Building footprints created from 2023 high density lidar point cloud in geodatabase format.

Block 1 (20 Mb)
Block 2 (66 Mb)
Block 3 (86 Mb)
Block 4 (45 Mb)

Building Service

(Coming soon)

for advanced users
The building footprint service will be available on the CT Geodata Portal.

Graphic of blocks from 2023 flight

 

Funding and Project Management

The 2023/2026 flight project is managed by Alfredo Herrera at the CT State GIS Office with assistance from the Aerial Imagery Acquisition Workgroup's eight members: Erik Snowden, lead (CRCOG), Dan Czaja (DESPP), Stuart Deland (DEEP), Eric Lindquist (DPH), Rich Gallacher (Town of Manchester), Mitch Gugliotti (DOT), and Emily Wilson (UConn). 

The project is funded by the American Rescue Plan with contributions from the CT Department of Transportation and the CT Department of Public Protection and Emergency Services.

Deliverables

Deliverables

Imagery

  • Statewide, leaf-off, 4-band orthoimagery tiles with 3 inch pixel resolution in GeoTIFF and MrSID formats, tide coordinated
  • True orthoimagery (nadir) over urban center and tall bridges and overpasses
  • Town mosaics in MrSID format

Elevation

  • Statewide QL1 Lidar point cloud with a minimum of 15 points per square meter with 13 classes, hydro flattened
  • Bare earth 2 foot DEM tiles in GeoTIFF format
  • Lidar-derived contours lines (1 and 5 feet)
  • Lidar-derived building footprints for all structures greater than 100 square feet.
  • 3D Terrain Model with 3D buildings

Documentation

  • FDGC/USGS compliant metadata
  • Reports including data acquisition, survey, production, control and calibration and quality assurance and accuracy

Citation

Please site the imagery as below. The elevation would be similar - just replace the data layer name.

CT State GIS Office. (2023). 2023 Aerial imagery. Retrieved from https://maps.cteco.uconn.edu/data/flight2023/.  

Image and Elevation Formats

Image Formats

GeoTIFF Highest quality image available here but also the largest file size by a lot
MrSID Generation 4 Compressed image file that supports all 4 image bands (blue, green, red, near-infrared)
MrSID Generation 3 Compressed image file with the smallest file size because it contains only 3 image bands (blue, green, red)

TIFF or TIF stand for Tagged Image File Format and is used for storing raster images of all kinds. Geo indicates that the TIF has a word file, called TWF that stores geographic information about the raster file.

MrSID stands for MultiresolutionSeamless Image Database. It is a way of compressing imagery so that it can be quickly viewed. LizardTech pioneered the MrSID technology. With each Generation, LizardTech has improved the functions of the MrSID files. MrSID Generation 3 improved upon Generation 2 by supporting unlimited files sizes, lossless encoding with optimization and manipulation options. MrSID Generation 4 improved upon Generation 3 by supporting multi-spectral and hyper-spectral imagery and an improved mechanism for composite mosaicking.

Elevation Formats

DEM -a raster based (pixel) Digital Elevation Model. The tiles available for download are in GeoTIFF format.

LAS/LAZ - is a lidar data exchange file which is a standard format for airborne lidar point data. LAZ is the zipped and compressed LAS.

Tiles and Sizes

Delivery Area and Tile Grid

Tiles and Sizes

Block Number of Tiles File size:
GeoTiff (GB)
File Size:
MrSID3 RGB (GB)
File Size:
MrSID3 CIR (GB)
File Size:
MrSID4 (GB)
Block 1, part 1 2110 793 58.9 58.9 78.6
Block 1, part 2 2157 803 60.8 60.8 80.4
Block 2, part 1 2252 843 64.1 64.1 85.1
Block 2, part 2 2220 833 63.2 63.2 83.9
Block 3, part 1 1956 729 55.3 55.3 75.7
Block 3, part 2 2016 752 57.0 57.0 75.7
Block 3, part 3 2612 974 73.9 73.9 98.2
Block 4, part 1 1467 547 40.9 40.9 54.7
Block 4, part 2 1512 564 42.2 42.2 56.3
Block 4, part 3 1712 639 48.5 48.5 64.4
Block 4, part 4 1672 623 47.3 47.3 62.8
Block 4, part 5 1695 632 48.0 48.0 63.7
TOTAL 23,381 8.73 TB 661.3 GB 661.3 GB 878.2 GB

 

File size:
Contour gdb
Number of contour sub-blocks File size: DEM GeoTIFFs  File size:
Point Cloud (laz)
Number off files
Block 1 4.98 GB 12 30.4 GB 1.27 TB 4267
Block 2 4.33 GB 12 31.5 GB 1.36 TB 4472
Block 3 5.66 GB 12 47.6 GB 1.78 TB 6584
Block 4 7.45 GB 18 57.8 GB 1.76 TB 8058
TOTAL 22.42 GB 54 167.3 GB 6.17 TB 23,381

 

The town mosaics are a MrSID mosaic that is a rectangle that fully includes each municipality with a small buffer from the borders. The range of file sizes is due to the shape and therefore size of the rectangle mosaics.

Number

 

File size: MrSID 3 RGB File size: MrSID 3 CIR
File size: MrSID 4 a
(lower compression)
File size: MrSID 4 b
(lower compression)
Town mosaics 169 611 GB 611 GB 1.99 TB 816 GB
(range from0.9 to 8.8 GB) (range from 0.9 to 8.8 GB) (range from 2.5 - 30.3 GB)  (range from 1.2 - 11.8 GB)

The Facts

23,381 tiles covering Connecticut. Each tile is 2500ft on a side or 0.224 sq miles, 143.5 acres and 6,250,000 sq feet.

The Facts: Imagery

Statewide. 4 bands (red, green, blue, near-infrared).  3 inch pixels.  GeoTIFFs.  MrSIDs Generation 3 and Generation 4. CT State Plane NAD 83 (2011)* Feet. Captured in March and April 2023 (leaf off).  Tide coordinated.

The Facts: Elevation

Statewide. USGS Quality Level 1, minimum of 15 points per sq meter. Minimally ground/non-ground classification. LAS files (point cloud). Bare earth 2 foot pixel raster tiles (called a Digital Elevation Model or DEM). 1 foot and 5 foot contours derived from Lidar. Captured in March and April 2023 (leaf off).  Tide coordinated.

* NAD 83 (2011) is the most current realization of NAD 83 published by the National Geodetic Survey and is consistent with the national Continuously Operating Reference Stations (CORS) Network.