Monday, February 19, 2007
Landsat Images for US States
Image by USGS
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The US Geological Survey has released a series of Orthorectified Landsat 7 images of all 50 states. These images are high resolution .tiff files that are suitable for plotting at poster size. File sizes range from 14 to 75 megabytes. A low resolution image for Arizona can be seen at right. The images are colorful state cut-outs on a black background with county boundaries, state flag, scale and latitude/longitude grid. Acquisition dates for the image data is 2000 (+/- one year) - all Landsat scenes were acquired between 1999 and 2001. The images are terrain corrected and rendered in a Universal Transverse Mercator projection. Information about how to obtain the image files can be obtained at the Earth Resources Observation and Science area of the USGS website. Labels: Geography, Satellite-Images
Friday, January 12, 2007
Urbanization and Environmental Geology
A few decades ago most geologists were engaged in the exploration and development of mineral resources. However, environmental geology and the application of geology to problems of the urban environment are slowly demanding the services of an increasing number of geologists. The United States Geological Survey has published "Professional Paper 1726 --
Rates, Trends, Causes, and Consequences of Urban Land-Use Change in the United States". This publication is a collection of 20 papers on urban land use change and its environmental consequences. Papers included are: - The Historical Development of the Nation's Urban Areas
- Cultural and Demographic Factors in Urban Decentralization in the United States—A Historical Overview
- Demographic Drivers of Lakeshore Urbanization in the Ozarks
- Economic Aspects of Urban Decentralization in Historical Perspective
- General Trends Regarding Aggregate Materials for Urban Development, With a Suggested Method for the Analysis of Aggregates Distribution
- Wrestling Sprawl to the Ground-Defining and Measuring an Elusive Concept
- Measuring Urban Sprawl and Extent Through Multitemporal Imperviousness Mapping
- An Assessment of Impervious-Surface Measurement Methods
- Comparing Impervious-Cover Densities on the Basis of Land-Use Types Between Sister Cities on the United States/Mexico Border
- The Use of Spatial Analytical Techniques to Identify Potential Brownfields Sites
- Road Densities for Urban Areas in the Conterminous United States
- Quantifying Urban Intensity in Drainage Basins for Assessing Stream Ecological Conditions
- Analyzing Albuquerque's Landscape Evolution in the 20th and 21st Centuries
- Change to Urban, Agricultural, and Forested Land in Central and Southern Maryland From 1850-1990
- Regional Landscape Change in the Northern Colorado Front Range
- A 30-Year Study of Urban Dynamics for the Municipality of Anchorage, Alaska, 1970-2000
- The Effects of Urbanization on Discharge and Suspended-Sediment Concentrations in a Southern California River
- Changes in Anthropogenic Impervious Surfaces, Precipitation, and Daily Streamflow Discharge-A Historical Perspective in a Mid-Atlantic Subwatershed
- Urban Growth and Seagrass Distribution Trends in Tampa Bay, Florida
- An Overview of the Stressors and Ecological Impacts Associated with Regional and Global Patterns of Population, Land-Use, and Land-Cover Change
Download the .pdf document for Rates, Trends, Causes, and Consequences of Urban Land-Use Change in the United States. Labels: Books-Publications, Geography
Wednesday, November 08, 2006
Free Wall Maps of Continents and Countries
Image by California Geographical Survey
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The California Geographical Survey is publishing a series of free wall maps that can be downloaded and reproduced for classroom use. These are large size maps that can be plotted and used as classroom teaching aids and displays. Published so far are maps of the United States, Africa, the Middle East, South Asia, East Asia, Australasia and South America. Dr. William Bowen, director of this mapping project says... "This latest project of producing a series of wall maps portraying the earth was begun at the request of a middle school teacher in California who needed free access to maps for classroom use."   
Images by California Geographical Survey - used with permission.Next in this series of free wall maps are Europe, North America, the Caribbean, the Pacific and greater Russia. More information about these maps, including copyright details, sizes, and download links can be found at the Wall Map Closet of the California Geographical Survey. Labels: Geography, Maps
Wednesday, August 09, 2006
South Africa and Lesotho Snow
It is a hot summer in the northern hemisphere and easy to forget that the southern hemisphere is in the midst of winter. Unusually cold temperatures in South Africa and Lesotho produced snow cover in the higher elevations. 
Images Adapted from NASA's MODIS Collection
 The image on the left is a MODIS True Color image showing the August snow cover. The image on the right is a MODIS Surface Temperature Image. The temperature scale can be used to determine the significant temperature range caused mainly by elevation in this area. View these images at higher resolution at the Earth Observatory website. Labels: Geography, Satellite-Images
Friday, July 29, 2005
Interactive Map of State High Points
Do you know where the highest point in your state is located? How about the highest point in Oklahoma? Now you can find out and zoom in to see it on a satellite image. 
Maps by GoogleVisit the High Points of All 50 States! Labels: Geography, Maps
Monday, May 30, 2005
Free Geographic Names Database Downloads
You can get a free download of the Geographic Names Information System file for your state at the USGS Geographic Names download page. These files contain an entry for each place name found on a USGS topographic map. Included in the entry are latitude/longitude, state, county, feature type, USGS quadrangle, elevation and more. Feature types include populated places, streams, lakes, waterfalls, hospitals and more. If you know a little bit about Microsoft Excel you can make a spreadsheet from the data like the one shown below. This will allow you to sort and prospect the data for a variety of purposes.  Labels: Geography
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