USGS - science for a changing world

Publications—Open-File Report 99–99

Computer Program for Point Location And Calculation of ERror (PLACER)

By Gregory E. Granato

U.S. Geological Survey Open-File Report 99–99

Prepared in cooperation with the Federal Highway Administration. A Contribution to the National Highway Runoff Data and Methodology Synthesis.


This report is available in Portable Document Format (PDF):

OFR 99–99 (208 KB) – 44 pages

Table of contents for the disk


A program designed for point location and calculation of error (PLACER) was developed as part of the Quality Assurance Program of the Federal Highway Administration/U.S. Geological Survey (USGS) National Data and Methodology Synthesis (NDAMS) review process. The program provides a standard method to derive study-site locations from site maps in highwayrunoff, urban-runoff, and other research reports. This report provides a guide for using PLACER, documents methods used to estimate study-site locations, documents the NDAMS Study-Site Locator Form, and documents the FORTRAN code used to implement the method.

PLACER is a simple program that calculates the latitude and longitude coordinates of one or more study sites plotted on a published map and estimates the uncertainty of these calculated coordinates. PLACER calculates the latitude and longitude of each study site by interpolating between the coordinates of known features and the locations of study sites using any consistent, linear, user-defined coordinate system. This program will read data entered from the computer keyboard and(or) from a formatted text file, and will write the results to the computer screen and to a text file. PLACER is readily transferable to different computers and operating systems with few (if any) modifications because it is written in standard FORTRAN. PLACER can be used to calculate study site locations in latitude and longitude, using known map coordinates or features that are identifiable in geographic information data bases such as USGS Geographic Names Information System, which is available on the World Wide Web.





The PLACER computer program

Installing PLACER


Manual-input method

Input-file method

Anatomy of an input/output file

Case studies

Case 1: Map coordinates

Case 2: Known locations



Appendix 1: Study-site locator form

Appendix 2: FORTRAN code for PLACER

This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.

Document Accessibility: Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools convert Adobe PDF documents into HTML or ASCII text, which then can be read by a number of common screen-reading programs that synthesize text as audible speech. In addition, an accessible version of Acrobat Reader 8.0 for Windows (English only), which contains support for screen readers, is available. These tools and the accessible reader may be obtained free from Adobe at Adobe Access.

Suggested Citation:
Granato, G.E., 1999, Computer program for Point Location and Calculating of ERror (PLACER): U.S. Geological Survey Open File Report 99-99, 36 p.

For additional information write to:

USGS Massachusetts–Rhode Island Water Science Center
10 Bearfoot Road
Northborough, MA 01532

or visit our Web site at:

U.S. Department of the Interior, U.S. Geological Survey
Persistent URL:
Page Contact Information: USGS Publishing Network
Last modified: Wednesday, 07-Dec-2016 17:45:12 EST
FirstGov button  Take Pride in America button