VCGI Imagery Program Frequently Asked Questions

  1. What does "compressed" imagery mean? What is JPEG 2000?
  2. How do I view compressed imagery (JPEG 2000) if I'm not using GIS software?
  3. Will my ArcView 3.x and ArcGIS 8.x software be able to view/use this compressed imagery (JPEG 2000)?
  4. Will my AutoCAD software be able to view/use this compressed imagery?
  5. Why can't I download imagery via FTP?
  6. Are there tutorials to help me learn how to use imagery?
  7. How do I make the Infrared band of the CLRIR imagery show up?

What does "compressed" imagery mean? What is JPEG 2000?

  • The following explanation is excerpted from the MassGIS web page. For more information, click on the link to that page below. "JPEG 2000 is an image compression standard for remote sensing digital imagery. This format, identified by the new “.jp2” file extension, offers many technical advantages:
    • State-of-the-art compression performance: JPEG 2000 permits high compression ratios with little or no degradation in image quality.
    • An image can either be compressed without any distortion or data loss, so that the reconstructed image is identical, bit for bit, to the original image (“reversible” or “lossless”), or it can be compressed so that there are slight perceptible differences from the original under normal viewing conditions (“lossy”).
    • An image can contain multiple embedded image quality layers
    • Certain parts of image can be coded in better quality than others
    • … and many others"

    MassGIS JPEG 2000 Information Page One option for dealing with compatibility issues (ArcView 3.x, ArcGIS 8.x, or CAD software) is described in #4 below - open the image with a viewer, then save as a .jpg or .tif (with a world file!).

2. How do I view compressed imagery (JPEG 2000) if I'm not using GIS software?

  • If you wish to view compressed imagery downloaded from this site, and you are not using GIS software, you may need to download a FREE viewer. Images with the extension ".jp2" are in JPEG 2000 format and may not be viewable with programs you use to view other graphics.
    • Geoviewer is LizardTech's free, standalone application for viewing geospatial imagery, vector overlays, and LiDAR files. LizardTech GeoViewer enables you to combine, view and export visual layers from varied sources, and provides tools for visualizing LiDAR data in MrSID and LAS formats. LizardTech GeoViewer supports a wide range of input formats {including JPEG 2000} and exports to GeoTIFF, PNG and JPEG.

3. Will my ArcView 3.x and ArcGIS 8.x software be able to view/use this compressed imagery (JPEG2000)?

  • There does not seem to be a plugin for ArcGIS 8.x that will allow the user to use JPEG 2000 files. Read about the options described in #4 below to download or create other formats.

    ArcView 3.x is a "end of life cycle" product. VCGI does not guarantee that the JPEG2000 files downloaded from our website will work with ArcView 3.x. However, if you choose to use ArcView 3.x then you can try downloading and installing the plugin noted below. Another option is described in #4 below - open the image with a viewer, then save as a georeferenced.jpg or .tif.

    ExpressView Browser Plug-in

    NOTE: VCGI does not support this plugin, and cannot guarantee that it will work with the JPEG2000 imagery downloaded from our website. If you have trouble using JPEG2000 files for any reason, we recommend that you order the uncompressed GeoTIFFs, which are available on media only. Refer to the Offline Data page.

4. Will my AutoCAD software be able to view/use this compressed imagery?

  • We are not AutoCAD users here at VCGI, so we did a web search on this subject. Please do your own search so that you can evaluate what you find!

5. Why can't I download imagery via FTP?

  • VCGI has had security breaches via FTP in the past, therefore we no longer offer FTP. However, all compressed image files can be downloaded from your browswer via HTTP. If downloading files one-by-one is too much trouble, VCGI recommends one of the following "download managers". They make it easy to download an entire directory of files in one job.

6. Are there tutorials to help me learn how to use imagery?

7. How do I make the Infrared band of the CLRIR imagery show up?

  • This FAQ about the Third vintage of statewide orthos shows you how!