We describe a method to render a height field given on a triangular mesh in a manner that is similar to wellknown cartographic map views. This approach utilizes hypsometric tints and creates topographic contour lines procedurally as part of the rendering process. We discuss essential graphical enhancement techniques such as line smoothing, gradient compensation, contour line visibility fading, ...

DISCLAIMER This document describes work undertaken as part of a programme of study at the Faculty of Geo-Information Science and Earth Observation of the University of Twente. All views and opinions expressed therein remain the sole responsibility of the author, and do not necessarily represent those of the Faculty. i ABSTRACT Historical topographic maps are distinct sources of spatial informat...

this study aimed to determine the prone areas for sugar beet planting with regards to their major effective factors. climatic data of 1998-2009 period were obtained from the local stations of khorasan razavi meteorological bureau. the topographic data including altitude, slope, slope direction, and tin layers were extracted from 1:250000 topographic maps of cartographic organization, iran. the ...

We propose a biologically motivated computational step, called non-classical receptive field (non-CRF) inhibition, to improve contour detection in images of natural scenes. We augment a Gabor energy operator with non-CRF inhibition. The resulting contour operator responds strongly to isolated lines, edges, and contours but exhibits a weaker or no response to edges that make part of texture. As ...

the dedicated satellite mission goce will sense various small mass variations along its path around the earth. here we study the effect of the earth’s topography and atmosphere on goce data. the effects depend on the magnitude of topographic height, and they will therefore vary by region. as the effect of the atmosphere and topography must be removed from the total gravity anomaly prior to geoi...

A n a u t o m a t e d s y s t e m h a s b e e n d e v e l o p e d t o g e n e r a t e g r i d D T M d a t a f r o m a r a s t e r i z e d topographic map. Conventional methods used are based o n either "raster-vector conversion" o r " l i n e following" and require a lot o f manual input and computing time. The system developed here is based on automated recognition of color contour lines from ...

Deriving GIS data from historical maps will provide the ability to compare historical geographic patterns to more recent GIS-layers. In this example, USGS topographic maps, scanned at Western Michigan University's W.E.Upjohn Center for Global Change provide experimental sources for the feature extraction techniques. USGS topographic maps contain standardized symbols and uniform colors, and the ...

We call "natural" image any photograph of an outdoor or indoor scene taken by a standard camera. We discuss the physical generation process of natural images as a combination of occlusions, transparencies and contrast changes. This description ts to the phenomeno-logical description of Gaetano Kanizsa according to which visual perception tends to remain stable with respect to these basic operat...