December 23rd, 2013 by Kevin Ward
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:
- “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.
- “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.
November 20th, 2013 by Kevin Ward
Nitrogen dioxide (NO2) is a gas that occurs naturally in our atmosphere. NO2 plays an important role in the formation of ozone in the air we breathe. Ozone high in the atmosphere helps us. It is like sunscreen, and it protects us from harmful ultraviolet (UV) rays from the Sun. Near the ground though, ozone is a pollutant. It damages our lungs and harms plants, including the plants we eat. Ozone occurs naturally in the air we breathe, but there’s not enough of it to hurt us. Unhealthy levels of ozone form when there is a lot of NO2 in the air. NO2—and ozone—concentrations are usually highest in cities, since NO2 is released into the atmosphere when we burn gas in our cars or coal in our power plants, both things that happen more in cities. Ozone pollution is worse in summer. NO2 is also unhealthy to breathe in high concentrations, such as on busy streets and highways where there are lots of cars and trucks. When driving, it is typically a good idea to keep the car windows rolled up and the car's ventilation set to “recirculate” so as to keep pollution out of the interior of the car. It is also important to reduce outdoor activities like playing or jogging if government officials warn you that air quality will be bad on a certain day.
These maps are produced using data from The Ozone Monitoring Instrument (OMI), on board NASA's Aura satellite and are available in daily, weekly, and monthly composites from October 2004 to the present.
August 21st, 2013 by Kevin Ward
The ocean’s salinity is key to studying the water cycle and ocean circulation, both of which are important to Earth’s climate. Differences in salinity play a major role in moving seawater around the globe. Below the wind-blown ocean surface, salinity and temperature drive circulation by controlling the “density” (mass per unit volume) of seawater. The weight of dissolved salt increases water’s density and when salinities are equal, colder water is denser than warmer water. In addition to moving salt and water, density-driven circulation is crucial to moving heat around our planet. The movement of heat by our ocean—for example, from the equator to the poles—is crucial to keeping Earth’s climate “just right.”
These maps are produced using data from the Aquarius instrument onboard the AQUARIUS/SAC-D satellite, a collaborative effort between NASA and the Argentinian Space Agency Comision Nacional de Actividades Espaciales (CONAE) and are available in NEO in weekly and monthly composites.
August 19th, 2013 by Kevin Ward
If you have been a user of NEO in the past you will, no doubt, notice many changes to the website. After many years (nearly 8!) we finally have a new look and have made several improvements to the navigation and functionality. That being said, much of the flow of the site is relatively unchanged. So let’s take a look at a couple redesigned elements of the dataset view page, which is one of the main functions of the site. (See this example for the full view.)
Starting below the main image, you will see the ability to toggle between different variations of the dataset. These variations will differ depending on which dataset you are viewing and for many the “View by satellite” toggle will not be relevant. Clicking on any of these buttons will both change the image above and the calendar view below.
Image download options
Currently viewing: At the top of the download options block you will see the date of the image you are currently viewing. The date may be either a year, a month + year, a single day, or a date range, depending upon what dataset you are viewing.
Downloads: This is where you can choose the format, size, and color of the image you would like to download. Select the desired file type from the list (for more information about the types of files that are available, click on the “i” help button next to “Downloads”), whether you want the image in color, as you see it on the page, or in grayscale, which can be useful for applying your own color palettes. Once you have made those selections, click on the dimensions you want (e.g., 360 x 180) and you can download the image.
Download Raw Data: If the source data file for this particular dataset is available online there will be a direct link to it here. These files can be in a variety of formats and are hosted by various data providers, not by NEO. We can help point you to the data owners if you have questions but otherwise we cannot provide support for these types of data.
Depending upon the dataset you are viewing, you will see one of three different types of calendar views on the page (the daily view is shown below). Use the blue slider to navigate between the time periods in the given year and the “Select Year” drop-down just above the calendars to change the year. Blue links will change the image shown when clicked. The calendar menus greatly improve your ability to browse the entire collection by date. The old way was a nightmare, I know; thank you all for your patience.
We hope that you like the new look of NEO and if you have any questions about the site please be sure to leave us a comment here or get in touch through our contact form.
March 6th, 2013 by Kevin Ward
The Washington Post featured imagery from NEO as part of their visualization illustrating changes in snow cover since 2010.
View Timelapse: A look at where snow has fallen at the Washington Post.
June 12th, 2012 by Kevin Ward
The Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite provides measurements of total column ozone, which is how much ozone is present in a column of the atmosphere stretching from the surface to the top of the atmosphere. Therefore, it includes both ground-level and stratospheric ozone. Ground-level ozone is especially common in industrialized areas during the summertime, and winds can blow ozone from urban areas into neighboring areas. Stratospheric ozone, however, absorbs harmful ultraviolet radiation known as UV-B. Because of stratospheric ozone’s protective function, the “ozone hole” over Earth’s southern polar region has concerned scientists since the late 1970s.
NEO now provides daily, weekly, and monthly composites of total column ozone from October 2004 to present.
June 29th, 2011 by Kevin Ward
These maps show how water stored on and in the land changes from month to month. The maps are blue where there is more water than average and red where there is less water. Water accumulates on land in rivers and lakes, as ground water and soil moisture, and as snow and ice. Scientists track water both to understand the water cycle and to monitor the availability of fresh water. The maps show that water levels change throughout the year with the seasons. Changes from year to year may reveal drought or an excess of water. These data currently include monthly composites from April 2002 to present.
April 11th, 2011 by Kevin Ward
These maps depict how much warmer or colder a region may be in a given month compared to the norm for that same month in the same region from 1951-1980. These maps do not depict absolute temperature but instead show temperature anomalies, or how much it has changed. These data currently include annual and monthly composites from January 1880 to present.
November 12th, 2010 by Kevin Ward
In this chapter from the Earth Exploration Toolbook, you can investigate satellite images displaying land surface temperature, snow cover, and reflected shortwave radiation data from NEO.
Download, explore, and animate these images using ImageJ, a public domain image analysis program from the National Institutes of Health (NIH). Then use the web-based analysis tools built into NEO to observe, graph, and analyze the relationship between the three variables.
November 10th, 2010 by Kevin Ward
Now you can also follow the action on Facebook! Hope to see you there: https://www.facebook.com/NASAEarthObservations
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