In this brief article, we will discuss potential for using freely available Landsat imagery to assess and monitor reservation lands. We also provide step-by-step instructions as well as links to instructional videos on their use. We present this problem/solution in the context of Native North American’s but the same principles apply to anyone or any group interested in assessing and monitoring natural resources at low cost.
Above: Landsat imagery is updated monthly and can be downloaded for free from the USGS.
Monitoring Natural Resources on Native American Reservations
Today, the US Department of Interior’s Bureau of Indian Affairs (BIA) holds 56.2 million acres of lands in trust for various Indian tribes and individuals. Approximately 46 million acres (81%) of this land is used for farming and grazing by livestock and game animals, yet Native American’s have not been the primary beneficiaries of these resources. According to the 2007 USDA Census of Agriculture, more than two-thirds of the farms and ranches on the Reservation lands, approximately 9 million acres, are leased by the Bureau of Indian Affairs to non-natives. The leasing of Indian Lands by the Federal Government dates back the the the Act of February 28, 1891 which amended the General Allotment Act to give the Secretary of the Interior the power to determine whether an Indian allottee had the “mental or physically qualifications” to enable him to cultivate his allotment. In such cases, the Superintendent was authorized to lease their lands to non-tribal members. In 1894, the annual Indian Appropriation Act increased the agricultural lease term to 5 years, 10 years for business and mining leases, and permitted forced leases for allottees who “suffered” from “inability to work their land,” and dramatically increased the number of leases issued across the country (Source: LLRP). These policies have meant that the Indian landowners across the country have been separated from their allotted lands, in many cases, for generations. In fact, many Tribal land owners know very little about their lands; where they are located, how they are being used, who they share ownership with, etc. This has had devastating impacts on the ability of landowners to manage and benefit from their land-based resources – economically or culturally. Furthermore, the combination of fractionated land ownership, indirect management of short-term leases by the Bureau of Indian Affairs, and insufficient monitoring and enforcement of the terms of leases has created a veritable tragedy of the commons where the lessees are able to over exploit tribal lands with little if any consequence. At a recent 2011 Working Session for Bureau of Indian Affairs Employees participants noted “that some trespassers run their cattle for months for free, “stealing the asset,” before a BIA agent notices.” Tribal members often accuse the BIA of failing to protect their lands, according to one resident of the Pine Ridge Reservation, quoted in Stromberg (2010), “The Bureau of Indian Affairs allowed a rancher to seriously overgraze that land. We got out there, there was nothing but cow poop, barren land. There was no grass, no wildlife, nothing. And we signed an affidavit, a complaint against him, and about 2 weeks later…he lost his lease.” Despite the fact that the BIA manages the leasing of Indian Lands, the agency is not a party to the lease and thus leave it up to the Native landowners and Tribal Governments to monitor lessees. This responsibility was affirmed through the American Indian Agriculture Resource Management Act of 1993 which “provide[s] for the establishment of a viable system for the management and administration of Indian owned agricultural lands; to enhance the capability of Indian ranchers and farmers to produce crops and products from such lands; to affirm the authority of the Indian tribal governments in the management and regulation of Indian agricultural lands; and to enhance the educational opportunities for Indian students in the management of Indian natural resources.” Yet, despite this authority, many tribes and Individual Indian landowners lack sufficient resources to adequately monitor their lands and the BIA leasing system. According to the Indian Land Working Group:
“Over the past 100 years, the government has implemented their “highest and best use” management policy by leasing Indian Land to non-Indians. This continues today, as is evidenced by the fact that of the 9 million acres of trust land classified as agricultural, 6 million is leased to non-Indians. A leasing cartel has been created because Indian landowners have had limited access to information and resources necessary to use and manage allotted trust lands.” (Excerpt from the ILWG Native Strategic Land Planning Workbook, 2005).
In recent years, advances in open source geographic information system (GIS) software and low-cost remote sensing now make it possible for Tribes and Individual Indian Landowners to monitor leasing on their lands more effectively and at lower cost. This document provides a brief overview of these tools, how they might be utilized to empower Indian landowners, as well as step-by-step instructions.
Monitoring Land Use on Native American Reservation Using LANDSAT Satellite Technology
The Landsat program is a series of earth orbiting satellites developed and maintained by the United States Government to collect high resolution imagery of the earth for use by scientists, government and industry. The Landsat program has been in operation since 1972 creating one of the largest and most accessible satellite archives in the world with new images updated approximately every month. In 2008, the U.S. Geological Survey opened up this archive, making it free of charge to the public on the website http://www.glovis.gov. Landsat images have an advantage over conventional aerial or satellite photographs because the images can be broken into their respective spectral bands of light (some not even visible to the human eye). Adjusting these bands can highlight light reflected from different types of vegetation, geology, and moisture (see below). This makes it possible to very quickly identify areas of concern and compare images across time.
Band Combination 7,4,2. Healthy vegetation will be a bright green and can saturate in seasons of heavy growth, grasslands will appear green, pink areas represent barren soil, oranges and browns represent sparsely vegetated areas.Dry vegetation will be orange and water will be blue. Sands, soils and minerals are highlighted in a multitude of colors
Band Combination 4,5,1. Healthy vegetation appears in shades of reds, browns, oranges and yellows. Soils may be in greens and browns, urban features are white, cyan and gray, bright blue areas represent recently clearcut areas and reddish areas show new vegetation growth, probably sparse grasslands. Source: http://web.pdx.edu/~emch/ip1/bandcombinations.html
Landsat can be a powerful tool for tribal natural resource programs, land and realty offices, environmental protection programs and advocates for the protection of tribal natural resources. Possible uses include:
- Identify potential overgrazing on rangelands.
- Determine if and when agriculture fields are plowed and/or harvested.
- Map the boundaries of prairie dog colonies
- Monitor the incursion of invasive species.
- Monitor forests for illegal logging
- Monitor the effects of drought
- Planning for land use management and zoning.
- Monitor erosion and desertification
Accessing and using Landsat Images
Landsat images can be accessed and utilized by anyone with a computer and internet connection. This tutorial will explain procedures for locating and accessing Landsat imagery using nothing more than a web browser to more advanced procedures using a Geographic Information System (GIS).
A. Locating Landsat Images for Your Region
LANDSAT satellites circles the earth from the North Pole to the South Pole every 103 minutes continuously collecting images along the way. It captures the Earth from East to West as as the earth rotates beneath it. To see a live feed of from the Landsat 8 satellite go to http://earthnow.usgs.gov. Each Landsat images covers a region of approximately 113 x 115 miles on the ground. Images are indexed by their geographic coordinates or by its specific “Path” and “Row” number. To find the path and row for a specific region you can enter the geographic coordinates for a certain place into the “Lat/Long” search boxes at www.glovis.gov.. Using geographic coordinates is a more accurate method of finding a specific location. If you don’t know the geographic coordinates for your location, you can look in the gazetteer of almost any atlas. If your town or feature does not appear in your atlas, look for the coordinates of a large city in close proximity to your site and use its coordinates. The U.S. Census Bureau offers an online U.S. Gazetteer for locations within the United States. When you enter geographic coordinates into Glovis, remember locations in the southern hemisphere need to have a minus sign in front of their latitude and locations in the western hemisphere need a minus sign in front of their longitude. You can also locate imagery by clicking your mouse on the desired location on the map just above the Path/Row search boxes. However, the map is very small which makes it difficult to locate a specific location. You can use the arrows to move to adjacent images. Once you have identified the right path and row, write it down for future reference. You can filter your results by date, image type and the maximum amount of cloud cover (using the “Max Cloud” dropdown).
B. Accessing LandsatLook Images
The easiest way to access Landsat imagery is by downloading LandsatLook Images. LandsatLook images are full resolution ready-made Landsat images in JPEG format. LandsatLook images are very useful if you want a full-resolution image, but do not want to download the full data set and make a composite RGB image yourself. To get started, you first need to create a free account on Glovis.gov. You can do so here:http://www.glovis.gov
- To download the LandsatLook image make sure the image that you want is selected within the yellow highlighted box then find and click Add at the lower left hand corner of the window.
- Next click Send to Cart. This will pop-up a new window with the scene info, to continue downloading click the green arrow hard drive graphic. Another pop-up will appear with some selections, if all you require is a natural color image (one that looks like you might take it from a simple camera out in space), select the LandsatLook “Natural Color” Image.
- Select Download Option (this options gives you a pseudo-natural color image using TM/ETM+ bands 5, 4, and 3 or MSS bands 2, 4, 1, all less than 12 Mb). See Below. The image can be viewed in a standard web browser or basic photo or graphics program.
Below is a video tutorial on how to download and view LandsatLook images using the free Quantum GIS software.
C. Georeferenced Landsat Images
Identifying specific locations within a standard LandsatLook image can be difficult because it lacks labels and because of its low resolution it makes it difficult to identify features like roads and towns. This is one reason it helpful to view these images using a geographic information system (GIS) where you can add layers on top of the Landsat Image like roads, towns, rivers, etc. This next section will discuss how to open and process Landsat images using the freely available Quantum GIS and the more common but relatively expensive ArcMap by ESRI. Landsat images can also be viewed in the free but much more limited ArcGIS Explorer. Georefencing is a process where information about the geographic location of the image is included with image. When you open a georeferenced image in a Geographic Information System (GIS) program, that image, like a puzzle piece, is automatically positioned at the correct geographic location relative to other images and layers like roads, towns, etc.
Opening Georefenced Landsat Images using Quantum GIS
Quantum GIS (QGIS) is powerful but user-friendly GIS software that runs on Windows, Mac OSX, Linux, and Unix. QGIS is freely available and open source with an extensive user and developer community. To download the latest version of QGIS go to http://www.qgis.org/. Once installed, make sure the GDAL and GRASS plugins are activated using the plugin manager found under the Plugins menu: Plugins> Manage Plugins> (Check the boxes to select plugins or use Select All). Here we will show you how to view Landsat TM4-5 and Landsat ETM SLC and SLC-off images. Note that SLC-off images are images produced after a device called the “Scan Line Corrector” malfunctioned which leaves lines of blank data across each image. It is possible to correct these images using data from adjacent pixels and/or other dates but for sake if simplicity, it is recommended that you stick to using the Landsat TM4-5 images. To acquire the images, use the procedure above but instead of downloading the LandsatLook images, you’ll want to select “Level 1 Product Geotiff. This will be a rather large file, approximately 170 Mb. Note: The file will appear with a name something similar to “LE70330342003106EDC00.tar.gz.” The file will come in a compressed folder. To decompress it, you’ll need to a free file decompression software such as WinZip. The decompressed folder will contain several separate files, including 7 separate “TIF” files. Each of the 7 files represents a different band of light. They can be viewed individually as grey-scale images or composited into a single image. Compositing makes it easier to analyze and compare images by comparing differences in composited colors. Below is a brief silent tutorial on how to use the free QGIS software to composite, display and change the color bands of Landsat TM images. Below is a video tutorial on how to download, process and view Landsat GeoTiff images using the free Quantum GIS Software. Below is a video tutorial on how to download, process and view Landsat GeoTiff images using ESRI’s ArcMap 10. If you have questions, comments or suggestions regarding this tutorial, please contact David Bartecchi This article was made possible by the Indian Land Tenure Foundation.