2002-2015

Update

July 8, 2016: Data available for the entire state!

DEMs from 2015 are now available for Western Mass. (from the Quabbin Reservoir to the MA/NY border) and a portion of the Blackstone watershed, filling in large areas with no previous coverage and replacing some older areas. With the new data, DEMs at 1-meter pixel resolution are now available statewide.

A large section of the Western Mass. area contains Quality Level 1 (“QL1”) data, which contains points at a higher density (point spacing) than Quality Level 2 (“QL2”) data. Both QL1 and QL2 have the same vertical accuracy. 2015 LAS data are expected to be available for download from NOAA’s Data Access Viewer by late August.

Overview

These twenty-one datasets contain Light Detection and Ranging (LiDAR) terrain files covering the entirety of Massachusetts. These data can be used for emergency response, drainage studies and hydrologic / floodplain modeling, development suitability analysis and infrastructure planning, identification of structures and other man-made features, habitat classification, vegetation mapping, and many other purposes. 

Each set represents a distinct data acquisition project with unique characteristics. Acquisition dates range from 2002 to 2015, and a variety of agencies and/or partnerships sponsored these missions – details can be found in the project-specific metadata. Differences include the instruments used to acquire the data, processing software, accuracy, point spacing, format, projection, tiling schemes, and availability of derivative products such as contours and breaklines. Point and raster data derived from the original LiDAR acquisition are available for each project area: The point data are in ASCII text files storing XYZ coordinates, binary LAS files (zipped as LAZ), or used to create bare-earth TINs; the raster DEMs (digital elevation models) are GeoTiffs or Erdas IMGs. The horizontal datum for all data is NAD83; the vertical datum is NAVD88. NOAA is now hosting most of our LAS data, which can be accessed for FREE through its Data Access Viewer.

Federal agencies are the primary contributors of the newer data. See the USGS' 3D Elevation Program page for an abstract and a link to a summary report for Massachusetts.

A free viewer is distributed by Fugro for viewing both LAS point files and the raster GeoTiffs, as well as shapefiles for referencing.

LiDAR Terrain Data Index

View Project Area Index Map pdf format of Lidar Index Map
file size 1MB (based on the LiDAR Index layer).

The following table summarizes data for the projects and contains links to download DEMs and metadata:
(**** see note below about downloading data in Internet Explorer)

Year /
Project Name
Acquisition DatesProjection /
Units
DEM Size ** /
Resolution
Point Size ** /
Format
Full
Metadata *
2015
Massachusetts
Spring & Fall 2015UTM Zone 18N &
19N Meters
21 GB***
1 m
600 GB
LAS
ZIP 162 MB
2013-2014
Sandy
Fall 2013 & Spring 2014UTM Zone 18N &
19N Meters
112 GB***
1 m
121 GB
LAS
ZIP 2 MB
2012
Merrimack Watershed
Nov. 2011-Jan. 2012UTM Zone 19N
Meters
1 GB
1 m
4.4 GB
LAS
ZIP 26 MB
2011
Northeast
Winter-Spring 2011UTM Zone 19N
Meters
17.5 GB
1 m
184 GB
LAS
ZIP 18 MB
2011
Nashua River
May 6-7, 2011UTM Zone 19N
Meters
3.14 GB
1 m
26.7 GB
LAS
ZIP 69 MB
2010
Blackstone River
Dec. 15-17, 2010UTM Zone 19N
Meters
1.18 GB
1 m
10.3 GB
LAS
ZIP 77 MB
2010
Charles River
Dec. 2-11, 2010UTM Zone 19N
Meters
1.93 GB
1 m
19.4 GB
LAS
ZIP 86 MB
2010
Concord River
Dec. 2-12, 2010UTM Zone 19N
Meters
2.95 GB
1 m
28.8 GB
LAS
ZIP 60 MB
2010
Narragansett River
Dec. 8-10, 2010UTM Zone 19N
Meters
1.86 GB
1 m
19 GB
LAS
ZIP 29 MB

To Download the DEMs for the above areas:

  • Open OLIVER and use the Identify tools to select your area of interest.
  • In the Identify results box click on the layer 'LIDAR Index (Most Current)'. The Feature details section will display the link for each tile you selected. Click on each link to download a .zip file containing the DEM.
  • To download many images in a more automated way, click the 'Save all records as' dropdown and save to an Excel file. Then:
    • Open Excel or a similar spreadsheet program, copy only the cells with the links and paste them into Notepad or other text editor and save as a text file.
    • Download the free WinWGet software and load the text file into a new job. Run the job and all the zipped images will be downloaded to a folder you choose.

The illustrated instructions (PDF) on the download process pdf format of USGS 2013/2014 Color Ortho Image Download Instructions
file size 1MB for the LiDAR DEMs are identical as those for the 2013-14 Ortho Imagery.

The datasets below are now redundant and in some cases inferior to the newer ones above.
(Links to detailed index maps of each project area are found on each DEM download page.)
2012
Hudson-Hoosic and Deerfield
Mar 20-Apr. 30, 2012UTM Zone 18N
Meters
2.35 GB
2 m Download
6 GB
LAS
ZIP 5 MB
2010
Nantucket
NAMA SPC Island Zone
Feet
434 MB
1 m [Download]
176 MB
ASCII, TIN
ZIP 15 MB
2010
Dukes County
NAMA SPC Island Zone
Feet
1.04 GB
1 m [Download]
1.5 GB
ASCII, TIN
ZIP 11 MB
2010
Quincy
Dec. 17, 2010UTM Zone 19N
Meters
721 MB
1 m [Download]
3.1 GB
LAS
ZIP 33 MB
2009
City of Boston
Nov. 9-10, 2009MA State Plane
Feet
7.6 GB
3.28 ft [Download]
9.6 GB
LAS
Text 1k
2006
Shawsheen River
Dec. 16, 2006MA State Plane
Meters
491 MB
1 m [Download]
415 MB
LAS
ZIP 14k
2006
Plymouth Co. S.
Nov. 10-26, 2006MA State Plane
Feet
457 MB
4 ft [Download]
13.7 GB
ASCII, TIN
ZIP 26 MB
2006
Bristol County
Nov. 10-26, 2006MA State Plane
Feet
394 MB
4 ft [Download]
11.2 GB
ASCII, TIN
ZIP 26 MB
2005
Blackstone River
NAMA State Plane
Feet
289 MB
8 ft [Download]
9.37 GB
TIN
Text 1k
2004
Southeast Pilot
April 30, 2004MA State Plane
Meters
136 MB
2 m [Download]
899 MB
LAS, TIN
ZIP 3 MB
2004
Hampden County
May-July, 2004MA State Plane
Feet
118 MB
10 ft [Download]
804 MB
ASCII
ZIP 6 MB
2002
Boston Area
April, 2002MA State Plane
Meters
3.16 GB
1 m [Download]
12.8 GB
ASCII
ZIP 40k

View/download a more detailed table of the above pdf format of LiDAR Terrain Data Project Area Summary
, including information on accuracy and point spacing.

Also available: April 2009 LiDAR and Ortho Imagery for the town of Amherst.

* Metadata .ZIP files include an overview text file and various documentation (PDFs, Word docs, and text files on acquisition, processing, QA, etc.) as delivered to MassGIS. Metadata varies by project area.

** DEM and Point file sizes represent the sum of all files as bzip2 or laz compressed archives for a project area and are provided to aid in ordering the data. The data file sizes will be larger when uncompressed, which is necessary in order to use the files in GIS and other software. Files sizes of individual rasters differ among and within project areas. These file sizes are listed on each project area's raster download page.

*** These DEMs are Erdas IMG files. All others are in Tiff format.

Notes:
 - LiDAR flight lines are frequently aligned with the terrain.
 - For flood mapping, LiDAR data may only have been processed near rivers and streams or along coastlines.

To learn more about LiDAR, a good place to start is the USGS Lidar base specification report.

What MassGIS Distributes

MassGIS is distributing two products:

  • Ground-classified .las files or bare-earth classified points represented by text files in XYZ format. (Nantucket text files are in XYZI format, where "I" represents the (uncalibrated) intensity of the LiDAR return.) LAS files represent a "point cloud", the three-dimensional composite of all returns from all laser pulses as determined from the aerial mission. These returns are analyzed to identify those that were probably reflected from the ground. NOAA is now hosting most of our LAS data, which can be accessed for FREE through its Data Access Viewer.

    The .las files for the 2012 Merrimack and Hudson-Hoosic and Deerfield areas have been compressed into .laz files. A .laz extension indicates that the LAS (.las) file has been compressed into a much smaller LAZ file with LASzip. LAZ files are only 7-20 percent of the original file size, and the process is completely lossless. LASzip is part of LAStools, a free download from http://rapidlasso.com/. All LAStools read, process, and write the compressed format directly without having to first decompress the file.
  • Bare-earth Digital Surface Model (DSM) rasters (aka DEMs - digital elevation models) in GeoTIFF and ERDAS Imagine formats, tiled to correspond to the .las or .xyz files. These data were either provided to MassGIS as a project deliverable, or created by MassGIS from the ground-classified points. In this context, DSM refers to a "bare earth" digital elevation model raster dataset without buildings or vegetation. In cases where MassGIS created a raster DEM where none was delivered, any return with a .las GROUND classification was converted to a multipoint feature class, and then a Terrain in ESRI ArcGIS 10. Breaklines representing various water features were included in the Terrain where available. The Terrain was then linearly interpolated to a floating-point raster (ERDAS Imagine .img file format). Finally, this large image dataset was “diced” into GeoTIFF tiles appropriate for each project. In some cases, only the IMG files as delivered are posted for download. Free converters can be found online.

    **** Note about downloading .bz2 files in Internet Explorer:

    MassGIS recommends using the Firefox, Chrome, or Safari web browsers to download the bzip2 compressed GeoTiff raster DEMs. If using Internet Explorer, when you click on a download link IE may attempt to display the binary contents of the file rather than prompt for downloading it. As a workaround in IE, right-click a .bz2 file, choose Save Target As..., and in the Save As dialog, choose "All Files" from the 'Save as type' dropdown. Then, in the "File name" box, change the .htm extension to .bz2 and click Save. When using Firefox, Chrome or Safari (the three browsers in addition to IE that MassGIS tested), you simply need to click on the .bz2 link and you will be prompted to download the file.

Using the DEMs in GIS Software

Unzipping .bz2 Files

The GeoTiff and IMG DEMs are provided for download in bzip2 compressed file format. The .bz2 files were created using the free and open source bzip2 1.0.6 software. Each .tif or .img file must be extracted from its .bz2 file by using a compression utility such as the free and open source 7-Zip and bzip2 software, or any tool that recognizes the .bz2 file format. Most Linux and Unix systems have bzip2 installed or have it included in their installation media.

Creating Pyramids and Statistics

To keep the file sizes as small as possible, the .bz2 downloads do not include accompanying pyramid or statistics files for the GeoTiffs and IMGs. When loading the .tif or .img into ArcMap, for example, the user may be prompted to build pyramids in order to speed image display.

More importantly, when first displaying the image it may appear as a single shade of gray, an artifact of the image not having statistics. To correct this, the image must be stretched (in the layer's Properties > Symbology tab > Stretch section in ArcMap). Since image stretching requires statistics, the user may be prompted to compute statistics when choosing a stretch method. When applied, the image will then display as expected. See the document LiDAR Image Stretching  pdf format of LiDAR Image Stretching
for illustrated details.


Last Updated 7/11/2016