Vertex ASF’s Data Portal

Welcome to Vertex!

 

Vertex is the Alaska Satellite Facility’s data portal for remotely sensed imagery of the earth. The ASF Datapool and the ASF Subsetter offer synthetic aperture radar data products available from the global ASF archive.

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ASF Datapool

The ASF Datapool contains pre-processed synthetic aperture radar data and images. SAR data, browse images and relevant metadata are easily visualized and available for direct download or bulk download in multiple formats through the Vertex ASF Datapool tab.
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Use Datapool »

Datapool


Overview Video

ASF Subsetter

The ASF Subsetter offers image mosaics of selected regions of the earth, and the ability to dissect preferred areas out of those images for immediate download. Choose from available data layers, map projections, and export formats through the Vertex ASF Subsetter tab. Read more...

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Subsetter


Overview Video


ASF Datapool Overview


There are two easy ways to learn how to use the ASF Datapool!


1. YouTube Videos

You can view the first of three ASF Datapool videos here, or you can see all of our training videos on our YouTube Channel located at www.youtube.com/AlaskaSatellite.

Subscribe to me on YouTube


2. Follow Three Steps

Simply follow the three steps listed below and you will be using the ASF Datapool in no time.

Step 1: Perform a Search

To begin a search, use your mouse to draw a two-point box over your area of interest. If you have a specific set of geographic coordinates identified you can enter them in the text box of the geographic region tab. The only parameter necessary to perform a search is the geographic region.

Choose a start and end date to bound the returned data; by default searches will return all data available over that area for the past two year. To search seasonally, click the seasonal search box and enter the months and years of interest. The ASF Datapool contains data first collected in 1991 and is continuously receiving data from active SAR missions.

The platform tab lists all of the SAR platforms with data in the ASF Datapool; the icon button on the right will provide more information about the platform and sensor.By default, all platforms are included in your search.

If you have a list of specific granules that you would like to research, paste those granule IDs in the granule list text box. Otherwise, just skip this tab.

Click the search button below the list of parameters to reveal data matching your search parameters in the ASF Datapool.

Geographic Region Filter

Step 2: Manipulate Search Results

Vertex returns all data available in the ASF Datapool that corresponds to your entered search parameters. Up to 1000 granules appear per page in the list; page controls and total number of returns are in the top right of the search returns list.

Scroll through the returned granule list on the right, as the yellow box on the map identifies the precise location of the data you are touching with your cursor.

There are two ways to filter, or narrow, your search returns; 1) the pre-defined platform post-search filters on the left or 2) the text filter at the top of the search returns list. The post-search filters on the left allow you to select specific beam modes, flight directions, and paths and frames of the satellite SAR data returned in your initial search. Select the specific filter attributes you are interested in and click the apply button. Your search results list and the map will soon reflect the results of you post-search filter choices. You can return to your original results by clicking reset within the specific platform filter or resetting all filters.

The second way to narrow your search results is with this text Find bar. Simply type any basic SAR parameter into this box and your search results list will filter according to your keystrokes.

Delete the text in the box to return to your original search results list.

Product profile pages are available for all returned data; click anywhere within the cell, or on the grey icon, to examine the profile page for that piece of data. Product profiles contain right-click downloadable browse images of the data, as well as some basic metadata about the granule. Also available through the product profile pages are two download options.

Post Search Filters
Product Profile Page

Step 3: Download Data

Direct download links for the data and the ability of adding the data to your download queue for bulk download at a later time are available through the product profile pages. You can also add to your download queue directly from the results list by clicking on the blue plus drop down icon within the data cell you are interested. If you have already filtered your results, you may want to choose the add all by type option at the top of the search returns list, which will add all data associated with the chosen processing level to your download queue.

The download queue provides information about your selected data, such as granule name, and anticipated file size, with the option of removing any data you may have decided not download after all. Download options here include a Google Earth KML, a csv file (includes direct links for downloading granules individually), and Metalink for bulk downloads. A download client is required to translate the Metalink bundled files into the individual zip files containing your data. A list of download clients and access links for those tested and recommended by ASF to receive Metalink bulk deliveries is also available through the download queue.

The unrestricted products UAVSAR and AIRSAR, are available for direct download and bulk download without the creation of an account on Vertex.

Restricted data will only be available to add to your download queue until you log in to your Vertex or ASF DAAC account. To login to Vertex, open the login modal at the top right of Vertex, and use your ASF DAAC user id and password. If you do not have an account on Vertex for accessing restricted data, please click the register button in the login modal for information on account creation. Once logged in, you can directly or bulk download all restricted data.

All processed SAR data delivered through Vertex is via zip file compression, with the use of zip64 for UAVSAR data products.

Download Queue

ASF Subsetter Overview


There are two easy ways to learn how to use the ASF Subsetter!


1. YouTube Video

You can view our ASF Subsetter video here, or you can see all of our training videos on our YouTube Channel located at www.youtube.com/AlaskaSatellite.

Subscribe to me on YouTube


2. Follow Three Steps

Simply follow the three steps listed below and you will be using the ASF Subsetter in no time.

Step 1: Select a Dataset

The ASF Subsetter offers numerous SAR mosaic datasets delimited as distinct seasonal datalayers. Using your mouse, choose a continent, then a unique datalayer for further examination. Select the note button next to a datalayer to access the Dataset Profile of accompanying information about that specific mosaic.

Dataset Profile

A mosaic Dataset Profile describes the sensor, acquisition conditions, and basic mosaic parameters. Each profile also contains a brief dataset abstract.

Available Dataset Screenshot

Step 2: Create a Bounding Box

Shift, click and drag a bounding box over the area you are interested in cutting, or subsetting, out of the moasicked image.

Bounding Box Screenshot

Step 3: Define Your Image Subset

This is the location to define the way you want your subset image of the mosaic to be delivered to you. Below are descriptions of the available download options.

Projection

A type of transformation that maps coordinates from the surface of a spheroid (i.e. Earth) to coordinates on a plane using mathematical algorithms

  • Geographic – This projects the mosaic in latitude/longitude format, standardized at the equator.
  • Google Mercator – This projection is in latitude/longitude Mercator format and compatible with Google applications.
  • Albers Equal-Area Conical – This projection is based upon a center point defined uniquely for each mosaic to which it applies.
  • North Polar Stereographic - This projection is suitable for use in the Northern hemisphere - north of 60°N onshore and offshore, including the Arctic.
  • Antarctic Polar Stereographic - This projection is suitable for use in the Southern hemisphere - south of 70°S onshore and offshore, specifically Antarctica.

Image Format

Vertex offers these image formats for immediate download: JPEG, GeoTIFF.

  • JPEG - JPEG is a compression method where images are available in the JFIF (JPEG File Interchange Format) file format. Viewable through most photo viewing applications.
  • GeoTIFF - GeoTIFF images retain embedded georeferencing information within a TIFF file, such as map projection, coordinate system, and datum. The GeoTIFF format is easily viewed in a GIS or TIFF viewing application.

Interpolation Method

Interpolation is an algorithm-based imaging method to increase (or decrease) the number of pixels in a digital image. Vertex uses these interpolation methods: Nearest neighbor, Moving average, and Bilinear interpolation.

  • Nearest neighbor: This is the simplest method and basically makes the pixels bigger. The color of a pixel in the new image is the color of the nearest pixel of the original image. If you enlarge 200% then one pixel will be enlarged to a 2 x 2 area of 4 pixels with the same color as the original pixel.
  • Moving average: The Moving Average method assigns values to grid nodes by averaging the data within the grid node's defined search ellipse. For each grid node, the neighboring data are identified by centering the search ellipse on the node. The output grid node value is set equal to the arithmetic average of the identified neighboring data. This method is desirable for reducing noise in dramatically downsampled data, and can give something approximating antialiasing for black and white linework.
  • Bilinear interpolation: This method uses the value of the four nearest input cell centers to determine the value on the output raster. The new value for the output cell is a weighted average of these four values, adjusted to account for their distance from the center of the output cell. This interpolation method results in a smoother-looking surface than can be obtained using nearest neighbor.

X Res/Y Res

Denotes the number of distinct pixels displayed in the X and Y dimensions. Units (e.g., decimal degrees, meters) depend on the associated projection; default resolution is the native pixel resolution of the datalayer.

Spatial Extent

Values represent the geographic coordinates of the area selected from the image using the bounding box tool. Subsets can only be selected from one datalayer at a time, and are limited to a rectangular shape.

Image Subset Screenshot

Map Legend

Number of matching frames

Please use the map and/or the search parameters on the left to select your search criteria.
Loading search results…
No results were found for your current search criteria.
Press shift-click and drag to define your bounding box
 








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