Data Sources
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Landsat
The following description of Landsat was provided by Tom Evans:
Landsat Thematic Mapper (Landsat TM) data have been the bread and butter for land cover change research for a while. Higher resolution data exist now, but a big benefit of Landsat data is that you can go back and acquire data from 1984 onward (when the first TM series sensor was launched) and compare apples to apples. In other words, you can compare data from 2010 (or 2000 or 1993...) to data from 1984 that has the same basic resolution and spectral information.
Landsat 5 was launched in 1984 and so from 1984 on we have 30 m resolution data available.
Landsat 6 blew up (well, really it just didn't reach orbit, but thinking it blew up is more dramatic)
Landsat 7 was launched in 1999, but in 2003 developed a technical error (SLC) that makes data after that non-optimal and most people don't use it.
But, the good news is that Landsat 5 is still working, and the data are free.
Landsat 5 has a repeat flyover period of 16 days. Generally you can find at least 4-5 usable images for most parts of the world for any given year.
The Landsat Data Continuity Mission (LDCM) is due to be launched 2012, within our project timeline. 30 m spatial resolution + 15 m panchromatic (just like Landsat 7)
Summary for Landsat Multi-spectral Satellite Imagery:
Landsat 5: 1984-present, 30 m spatial resolution multi-spectral data, Free, 16 day repeat flyover period
Landsat 7: 1999-2003, 30 m spatial resolution multi-spectral data, 15 m panchromatic (single band grayscale, like black/white photo). Free.
Landsat LDCM: 2012-?, cost ?
USGS Landsat Data Site:
Web Site: http://landsat.gsfc.nasa.gov
USGS Metadata Schema for Landsat data query response:
http://landsat.usgs.gov/metadata_service/schema/metadata.xsd
The entire collection of metadata can be downloaded from http://landsat.usgs.gov/metadatalist.php and is updated daily. The metadata is available in 5 flavors:
Landsat 7 ETM+ (SLC-on) Landsat 7 ETM+ (SLC-off) Landsat 1-5 TM Landsat 4-5 MSS Landsat 1-3 MSS
For actually downloading data there are a couple of GUI interfaces available through the USGS and other web sites. These generally require a login (free) and then the user can download. There does not seem to be an API available (at least through the USGS). However, the GLCF site (see below) says that the Landsat data is available via FTP from the USGS "All Landsat Global Land Survey (GLS) collections are available by individual scene for free via FTP at http://glovis.usgs.gov"[1]. The URL given on the GLCF web page lins back to the interactive search GUI at the USGS.
Some other sources of the data are listed at:
http://landsat.gsfc.nasa.gov/data/reduced.html
Global Land Coverage Facility (GLCF)
The Global Land Coverage Facility (GLCF) at the University of Maryland - College Park, has data that is available from an FTP site (ftp://ftp.glcf.umiacs.umd.edu/). Although we would need to see if there is a consistent naming convention between the USGS metadata and the GLCF FTP site. Also, we need to make sure that our site would throttle any downloads so that our IP is not cutoff from access by aggressive downloads (see the welcome.msg on the FTP site). Since the GLCF references back to the USGS, there may be a consistent naming of the files in te GLCF FTP site and the USGS metadata.
There is also a product search page at the GLCF (http://glcfapp.umiacs.umd.edu:8080/esdi/index.jsp) and download links there, so we may be able to download products from the ftp site since the download links are to a GLCF FTP site.
The GLCF also has instructions for downloading using wget, but we would first need to know what files to download. They describe doing this through the search interface, but possibly it could be done through the USGS metadata - we would need to check further.
Also, instructions on downloading ESDI layers (http://glcfapp.umiacs.umd.edu:8080/esdi/index.jsp) but we need to check with Tom if this would be useful.
Possibly a useful link on data formats: http://glcfapp.umiacs.umd.edu:8080/esdi/index.jsp
EOS Webster
This site at the University of New Hampshire is also supposed to have Landsat data available (free).
http://eos-webster.sr.unh.edu/home.jsp
Their Landsat holdings seem to be limited to the U.S., Russia, some of South America (mainly Brazil), and some of Southeast Asia. They may have other useful data. It has a search interface, but not sure if it has an FTP interface.
Terra
Web Site: http://asterweb.jpl.nasa.gov
Aster data is produced on-demand or existing data is available through three sources:
1. The Warehouse Inventory Search Tool(WIST) which has an interactive interface (click on the Enter WIST link):
https://wist.echo.nasa.gov/~wist/api/imswelcome/index.html
2. GloVis (see discussion of Landsat data). This is an interactive search tool.
3. Land Processes Distributed Active Archive Center (LP DAAC) Data Pool
https://lpdaac.usgs.gov/lpdaac/get_data/data_pool
The Data Pool has FTP access of the data and metadata for Aster, Modis Aqua, Modis Terra, and Modis Combined. However, one caveat is that the site says in regard to Aster holdings. "The most recent two years of ASTER "Version 3 Level-1B Registered Radiance at the Sensor" products for the U.S. and territories is available for Data Pool access." The tutorial for the Data Pool says that it has Aster data only for the U.S. and territories, and only for 2 years. It is Level-1B data (not sure if that is a limitation for IFRI or not). However, does have global MODIS data.
ASTER GDEM Data
Following is an update from an exchange with Tom Evans (IU):
Digital Elevation Model (DEM) is a generic term for raster elevation data. You need this kind of data to characterize land suitability (how steep terrain is in different areas) and in some cases to appropriately process satellite imagery (since the reflectance values in satellite images are affected by surface slope angle). The GDEM data is global coverage, but since it is elevation data, we only need to load this once.
Available at: http://www.gdem.aster.ersdac.or.jp/
These "ASTER GDEM" data are 30 meter resolution, which is dramatically better than the previous global elevation dataset. And the ASTER sensor is on the TERRA platform.
From the Aster Site: - Conditions of ASTER GDEM use
When registering, it is required to agree to the conditions of data use(Agreement for GDEM distribution and data use), such as prohibition of secondary distribution of GDEM original data, credit title obligation in the case of displaying GDEM original data or the products produced by GDEM on Internet, scientific journal or any other publications.
Based on their FAQ page, in response to a question on distribution, non-reversible data can be distributed:
Reversible data: CAN NOT be redistributed
1) Data whose unit is simply changed, so the original x-y-z values can be recovered 2) Data whose format is simply transformed (e.g., transformation from GeoTIFF to ESRI format) 3) Mosaicked GDEM data 4) Data subset at better resolution than the native (1 arc-second)
Unreversible data: CAN be redistributed
1) Paper materials on which the image produced from GDEM is printed 2) Re-projected images involving re-sampling 3) Data whose format is transformed so that the data can not be converted back to the original data 4) Value-added product (e.g., flyby movie)
Question: Is MODIS data useful for IFTRI?
The MODIS data comes in two flavors: daily products and composit data, with the composit data being available for approximately 1 year and daily data being available for 4 days.
TerraLook
Aster also has a tool called TerraLook
http://asterweb.jpl.nasa.gov/TerraLook.asp
Which has data going back to the 1970's and includes Aster data. The data is dwnloadable via their FTP site (ftp://asterweb.jpl.nasa.gov/Collections/) and it does have sections for Africa, Central and South America, and Asia. One issue with TerraLook is that each file has an associated Notes page, buy it is not in XML format, so we would need to determine if the format is consistent.
Advanced Land Observation Satellite (ALOS)
Web Site: http://www.eorc.jaxa.jp/ALOS/en/index.htm
The GLCF (see above discussion of Landsat data) is also a source for ALOS data - see the web page: http://glcf.umiacs.umd.edu/data/alos/index.shtml As an educational institution we would be eligible for reduced pricing of 25,000 yen (about $208 according to their web site) but the data could not be shared among users. However, IFRI may be connected to a Jaxa research project - we would need to check.
PRISM Data
(Snipped out of an email from Tom Evans)
PRISM sensor data, a companion to the ALOS data, are high resolution (2.5 m) panchromatic (i.e. grayscale instead of multi-spectral like Landsat) and for areas where Google Earth imagery are low resolution, provides another option for generating training data.
http://www.eorc.jaxa.jp/ALOS/en/about/prism.htm
Tools
This section is for links to tools that may be of use in the project.
1. LP DAAC tools: https://lpdaac.usgs.gov/lpdaac/tools
2. Web Service Interface for USGS:
http://gisdata.usgs.gov/XMLWebServices/Inventory_Service.php
However, not sure from the user guide if this is only U.S. data.
Other Data Sets
This section lists web sites with other possible data sets - not sure if they would be of interest.
1. Global Land Cover Characterization (GLCC)
http://edc2.usgs.gov/glcc/glcc.php
2 List of USGS Satellite Data Products:
http://eros.usgs.gov/#/Find_Data/Products_and_Data_Available/Satellite_Products
3. List of USGS Land Cover Data Products:
http://eros.usgs.gov/#/Find_Data/Products_and_Data_Available/Land_Cover_Products
4. NASA List of Other Low-Cost Data Sites:
http://landsat.gsfc.nasa.gov/data/reduced.html
