DOI:10.5593/SGEM2013/BB2.V1/S11.032

# POLYNOMIAL GEOREFERENCING METHOD FOR OLD MAP SERIES

J. Cajthaml
Monday 5 August 2013

References: 13th SGEM GeoConference on Informatics, Geoinformatics And Remote Sensing, www.sgem.org, SGEM2013 Conference Proceedings, ISBN 978-954-91818-9-0 / ISSN 1314-2704, June 16-22, 2013, Vol. 1, 859 - 866 pp

ABSTRACT

Old maps are very frequently used for environmental applications nowadays. The old map can be used for landscape reconstruction, studying of changes in the environment, for analytical studies using geographical information systems or for computational geometry based analysis [1]. When the old map was created on the only map sheet standard transformation methods for its georeferencing could be used (e.g. similarity, affine, polynomial).
If we are working with old map series the georeferencing methods should be more complex. It is necessary to solve edge matching of adjoining map sheets in order to create seamless map without any gaps.
Recently, the new method of georeferencing for map series using affine transformation and edge matching has been published. The method is based on the overall adjustment of all transformation parameters with conditions of identical shape of matching edges. However, affine transformation can get unacceptable positional errors when working with very old maps. Standard methods of polynomial transformations are used in these situations when having the only one map sheet. This article describes the new proposed method based on the overall adjustment of second order polynomial transformation parameters with edges identity conditions for old maps series. The method solves identity of matching edges, even with its polynomial shape.
The great advantage of the new method is possibility of creating the seamless map of relatively large area. In the testing area of the Usti region 39 adjoining map sheets of the First Military Mapping Survey of Habsburg Empire were georeferenced and the results can be compared with the results of affine transformation with edge matching previously mentioned. The new second order polynomial method slightly distorts the original images of the map sheets, but the positional mean error has been reduced by half.
The new polynomial georeferencing method for old map series can be used any time when the old imprecise map series have to be georeferenced into the seamless map. It is an alternative to using affine transformation with edge matching constraints or other complicated methods.

Keywords: georeferencing, old maps, polynomial transformation, adjustment, edge matching

PAPER DOI:10.5593/SGEM2013/BB2.V1/S11.032: POLYNOMIAL GEOREFERENCING METHOD FOR OLD MAP SERIES