Rubber Sheet Transformation In Gis

Rubber sheeting is a useful technique in historical gis where it is used to digitize and add old maps as feature layers in a modern gis.

Rubber sheet transformation in gis.

The affine transformation function is. The modify features pane appears. Rubber sheeting may improve the value of such sources and make them easier to compare to modern maps. The input point features represent identity links that hold source positions unmoved during the rubbersheeting process.

Rubbersheeting makes spatial adjustments to align the input feature locations with more accurate target feature locations based on the specified rubbersheet links. Before aerial photography arrived most maps were highly inaccurate by modern standards. On the edit tab in the features group click modify. Expand alignment and click transform.

Geometric correction of them. An affine transformation can differentially scale the data skew it rotate it and translate it. Qgis is a free open source gis package. It makes possible comparing and overlaying multiple maps from different time periods.

Click the spatial adjustment menu point to adjustment methods then click rubbersheet to set the adjustment method. Click rubbersheet for the adjustment method so you can set additional options for rubbersheeting. Click the spatial adjustment menu point to adjustment methods then click a transformation method. Click either the natural neighbor or linear method and click ok.

Qgis georeferencer plug in provides a number of transformation types including thin plate spline which enables full rubber sheeting. The input link features represent the regular links. Click the adjustment methods drop down arrow and click rubbersheet. Rubber sheeting topological process of stretching or shrinking a subarea or portion of a map or image to fit in registration with selected control points.

Click the options button. This drawback brings us to the idea of incorporating the historical maps into gis after rubber sheet transformation i e. You can press and hold the spacebar to temporarily turn off snapping as you create anchor points and draw displacement links or rubber sheet area polygons. Geometric distortions commonly occur in source maps.

Click the spatial adjustment menu and click options. Click the general tab. Affine similarity and projective. Click the spatial adjustment menu and click options.

X ax by c y dx ey f. Rubbersheeting is used to make small geometric adjustments in your data usually to align features with more accurate information. Root mean square error measure of registration accuracy used during digitizing and coverage transformations. Used to control rubber sheeting and adjustment operations.

The graphic below illustrates the four possible changes.