NEO News

Raster and Floating Point GeoTIFFs: What is the difference?

When you are considering which format to download for a NEO image, there are two GeoTIFF format options: GeoTIFF (raster) and GeoTIFF (floating point). This can be confusing at first. Let’s take a look at both examples using the Chlorophyll Concentration dataset to distinguish the two formats.

Here is a screenshot showing the Downloads box with an arrow pointing to where you can select either GeoTiff format and a circle around where the raw data is available for download.
This is the Aqua/ MODIS Chlorophyll Concentration GeoTIFF (floating point) image for the month of October 2020.

The image above is what downloads when you select GeoTIFF (floating point). This is a floating-point image file where each cell has a number with a decimal (ex. 1.1111). We call this format “data-like” for our purposes because it has been scaled and resampled as part of the processing of the original source data for NEO and the files are simplifications of the original data. Keep this in mind when you are using NEO imagery for analysis—our datasets should not be used for scientific research because they were not calibrated to the precision needed for scientific analysis.  If you want to do your own processing for scientific research, choose the “Download Raw Data” option located in the Downloads box.

This is the Aqua/ MODIS Chlorophyll Concentration GeoTIFF (raster) image for the month of October 2020.

To simplify even further, the GeoTIFF (raster) above is an 8-bit color image. The values are stored as 8 bit grayscale and the color table is applied on-the-fly based on those values.

If you have any additional questions or need further clarification, please email us through the “Contact Us” button below.

View NEO Imagery on a Sphere

There are several companies and organizations that provide spherical projector technology, but the first one I had ever heard of was Science on a Sphere (SOS) created by the National Oceanic and Atmospheric Administration (NOAA). Originally envisioned in 1995 by Dr. Alexander “Sandy” MacDonald and later patented in 2005, these Science on a Spheres (and other variations) are in hundreds of locations across the United States and abroad to help increase understanding of Earth’s complex processes.

Image showing Dr. James Garvin (on right), giving a presentation on "Science On a Sphere" to Yuri's Night guests.
Dr. James Garvin (on right), gives a presentation on “Science On a Sphere” to Yuri’s Night guests. Credit: NASA

In support of these visualization systems, NEO provides an archive of time-lapse global imagery to display in spherical projections located in the NEO SOS Archive. NEO uses the Content Creation Guidelines by NOAA to provide a time series in the preferred projection, image format, and resolution. There is also a labels.txt file available with each dataset to label the images with the correct acquisition, a color bar file to provide context to each time series, and a PIP text file (.SOS) that points to the labels and color bar file along with extra features like fade in time and frame rate. Please see the SOS Remote App manual to learn how to display NEO’s time-series datasets on your display system using the SOS Remote App.

Example directory with supporting files to display time series of Active Fires dataset on the Science on a Sphere.

This service started based on requests and only has part of the NEO archive available. If you see a dataset that is not in the archive on our site and you would like it for your spherical visualization, please send us an email using the Contact Us link below.

Here is a preview of some of the datasets we currently have available in the SOS Archive:

Active Fires from Terra/ MODIS

Image showing Active Fires for September 2020 on a spherical projection.
Image showing Active Fires for September 2020 on a spherical projection.

Aerosol Optical Thickness (Depth) from Terra/ MODIS

Image showing Aerosol Optical Thickness for October 2020 on a spherical projection.
Image showing Aerosol Optical Thickness for October 2020 on a spherical projection.

Chlorophyll Concentration from Aqua/ MODIS

Image showing Chlorophyll Concentration for October 2020 on a spherical projection.
Image showing Chlorophyll Concentration for October 2020 on a spherical projection.

Land Surface Temperature Anomaly (Day) from MODIS

Image showing the Land Surface Temperature Anomaly during the day for October 2020 on a spherical projection.
Image showing the Land Surface Temperature Anomaly during the day for October 2020 on a spherical projection.

Net Radiation from CERES

Image showing Net Radiation for July 2020 on a spherical projection.
Image showing Net Radiation for July 2020 on a spherical projection.

Outgoing Longwave Radiation from CERES

Image showing Outgoing Longwave Radiation for July 2020 on a spherical projection.
Image showing Outgoing Longwave Radiation for July 2020 on a spherical projection.

Rainfall from TRMM

Image showing Rainfall from TRMM for August 2016 on a spherical projection.
Image showing Rainfall from TRMM for August 2016 on a spherical projection.

Reflected Shortwave Radiation from CERES

Image showing Reflected Shortwave Radiation for July 2020 on a spherical projection.

Sea Ice Concentration from SSM/I / DMSP

Image showing Sea Ice Concentration and Snow Extent for November 18, 2020 on a spherical projection.
Image showing Sea Ice Concentration and Snow Extent for November 18, 2020 on a spherical projection.

Sea Surface Temperature from Aqua/ MODIS

Image showing Sea Surface Temperature for August 2020 on a spherical projection.
Image showing Sea Surface Temperature for August 2020 on a spherical projection.

Sea Surface Temperature Anomaly from AQUA/AMSR-E

Image showing Sea Surface Temperature Anomaly for September 2011 on a spherical projection.
Image showing Sea Surface Temperature Anomaly for September 2011 on a spherical projection.

Questions asked frequently at NEO

After many years of serving the public with global visualizations of Earth’s system processes, we gathered the most frequent questions visitors of our site ask and answered them for you. The FAQs page can be found on the home page and lives here: https://neo.sci.gsfc.nasa.gov/faq/. Please look these questions over and see if they answer questions you may have had already or discoveries that will help understand our site better.

If you read through the page and still have your own unanswered questions we did not cover, please send us an email using the contact form below and we will make sure you are heard.

NEO FTP Service No Longer Available

Effective June 13, 2019, the NEO File Transfer Protocol (FTP) service is no longer available. It has been replaced with access via HTTPS.

NEO FTP Service is Retiring

NASA is in the process of deprecating the use of FTP protocol for file access across the agency. As a result, downloading files from NEO via FTP may no longer be available after April 15, 2019. NEO will support bulk downloading options via HTTPS, but FTP client software applications will no longer be able to access NEO holdings. Similarly, if users are using FTP command line utilities or scripts to download from the archive, those will need to be converted to using HTTPS-access methods.

The directories containing the bulk files can be found at https://neo.sci.gsfc.nasa.gov/archive/ Additionally, you may also use our Web Mapping Service (WMS).

For users who have scripts or command line experience, we recommend using either wget or curl to facilitate downloading from the bulk archive. There is quite a bit of documentation and examples that can be found simply by searching, or even just looking at the wget man page, but here are a couple wget examples:

If you want to maintain an up-to-date mirror of a specific directory, retrieving only the PNG files:

wget --no-directories --no-host-directories --no-parent --recursive --mirror --accept "*.PNG" -l1 https://neo.sci.gsfc.nasa.gov/archive/rgb/MOD_LSTD_M/

Same as above, but get only the images from 2007 (for example):

wget --no-directories --no-host-directories --no-parent --recursive --mirror --accept "*2007*.PNG" -l1 https://neo.sci.gsfc.nasa.gov/archive/rgb/MOD_LSTD_M/

If you are not comfortable using command line utilities to download NEO imagery, there is a growing number of graphical interfaces to facilitate downloading over HTTPS. Some are stand-alone applications, some are browser plugins. You can find these applications by searching on “download multiple files from website.”

Data-like File Formats: CSV and floating point GeoTIFFs

In addition to the standard file formats that we support in NEO—JPEG, PNG, GeoTIFF, and GoogleEarth—many (not all) datasets support two additional “data-like” formats: CSV (comma-separated values) and floating point GeoTIFF. When you choose one of these formats for download, there are a few details that should be taken into consideration.

  • The values that these files contain have been scaled and resampled for visualization purposes in NEO and should not be considered for rigorous scientific examination. At best they are useful for basic analysis and trend detection but if you are interested in conducting research-level science we recommend that you use the original source data (which are not hosted by NEO, but we can assist you in identifying the source).
  • CSV files can get quite large at full resolution. For example, a 3600×1800 CSV file can get to around 61MB. If your software has difficulty opening a file of that size then please select a smaller resolution (e.g., 1440×720).
  • There are two flavors of CSV available in NEO:
    1. “Regular” CSV which includes the text-only values at the resolution the user specifies. This format is suitable for Excel (2007 and later) and many other applications.
    2. “CSV for Excel” In Excel versions prior to 2007, worksheets could not support more than 256 columns. To remedy this, this format option is resized to 250×125. The first row contains the longitude values for the center of the cell and the first column contains the latitudes.
  • Floating point GeoTIFFs contain 32-bit numerical data along with the geolocation information that is standard for the Geo format. These files can also get large as they are not internally compressed—e.g., a 3600×1800 GeoTIFF can be around 25MB.

These formats are not available by default on our ftp site but if you are interested in obtaining a long time series of a dataset in one of these formats, please contact us and we can perform a customized export to the ftp site in the format you need.

NEO Web Mapping Service (WMS)

The NEO Web Map Service implementation strives to open up the NEO collection to users who wish to access its contents via machine-to-machine interaction. WMS gives users the ability to access maps from any implementing service using a standardized programming interface.

Read more about NEO WMS.

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