Fact Sheet No.32 Ranch Maps

Introduction

Ranch maps can be as simple as hand sketches or more elaborate, utilizing aerial photographs, soils maps, and topographic maps. Notes or drawings added to aerial photographs will provide important site specific information. For some sites, old aerial photographs can be obtained, and when used with newer photographs are useful in identifying changes over time.

Topographic Maps

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The United States Geological Survey has prepared topographical maps for most areas in the United States. These maps illustrate geographic features of the landscape (hills, valleys, streams, etc.). These maps come in two sizes: 15 minute (1:62,000) and 7.5 minute (1:24,000) series. The 15 minute series covers an area of about 230 square miles. Four 7.5 minute maps cover the same area and therefore show more detail.

Topographic maps can be obtained from the US Geologic Survey at:

Earth Science Information Center

US Geologic Survey

345 Middlefield Road

Menlo Park, CA 94025

Phone: (415) 329-4390

Or USGS topographic maps can be purchased at outdoor recreation or sporting goods stores. Look in the yellow pages under maps for additional sources. Sometimes the Natural Resources Conservation Service (formerly Soil Conservation Service) office has USGS topographic maps and may be able to provide photocopies

Aerial Photographs

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Aerial photographs make an excellent base map for ranch planning. Two sources from which aerial photographs can usually be ordered are the local Consolidated Farm Services Agency (CFSA) or WAC Corporation in Eugene, Oregon.

Aerial photographs can be ordered in two different forms, and they can be enlarged to different sizes. They can either be printed on photographic paper, so that they look like a regular black and white photograph, or they can be ordered on mylar (also called film positive) from which "blackline" prints can be produced at a blueprint shop. The blackline prints are not as crisp as the regular photographic prints, but they are inexpensive to print (approximately 50¢ each), so you can make many copies from one mylar. The initial cost of a mylar is approximately $5 to $10 higher than a print on photographic paper.

Advantages of the mylar are that many copies can be printed inexpensively, and the mylar itself can be written on in erasable ink so that your ranch map and notes can be duplicated. The advantage of a photographic paper print is that the image is crisper and slightly easier to read, but there is no good method for reproducing additional copies of this type of photograph. Erasable ink or tracing paper overlays should be used on photographic paper prints.

The original photographs are taken at a scale of 1" = 2640' (WAC) and 1" = 3333' (CFSA). These scales are calculated from average flight elevations, so they are not exact. Commonly used scales for enlargements are 1" = 500' and 1" = 660'. Photographs can usually be enlarged to 1" = 200', though they lose clarity at this scale. At a scale of 1" = 660', one square inch is equal to 10 acres.

To order, go to the CFSA office and fill out an order form. Check in the phone book under US Government, US Department of Agriculture, to find their location. Orders are filled in approximately 40 days. Two feet by two feet is a standard size print provided by ASCS. At a scale of 1" = 660', this size print would cover 5,760 acres. Cost is $30 for a film positive and $20 for a photographic paper print.

In some instances specific ranges or sites may occur on two maps. For those sites, a special request can be made to combine maps. These requests should be further described with assistance from the CFSA office.

To order from WAC, send a FAX of a USGS topographic map with the property outlined and specify the scale and type of print (mylar or photographic paper) that you want--orders are filled in approximately two weeks. Aerial photograph prices are based on the size of the enlargement. Minimum orders in 1995 were $35 for photographic paper and $40 for mylar. Coverage for a 500 acre ranch, at a scale of 1" = 500' should be within these minimums.

To order from WAC:

WAC Corporation

520 Conger Street

Eugene, Oregon 97402-2795

Phone: (800) 845-8088

FAX: (503) 485-1258

Soil Survey Maps

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Soil surveys, including maps, can be obtained from the USDA Natural Resources Conservation Service. Modern soil surveys are aerial photos with soil mapping units superimposed. The soil survey includes soils descriptions and management information.