Rasta is a software that can provide high-standard functions for images display, drawing, modification, transformation and georeferencing. Rasta is the ideal solution for engineering, topography and cartography works which demand an easy management of big-size images. Rasta can be used to obtain hybrid raster-vectorial designs.
Rasta is the solution offered by SierraSoft to obtain high-performance display, plotting, transformation, editing, mosaicing and georeferencing of black and white or color images. Rasta is an extremely useful tool for those who deal with territorial problems, since it allows to load on screen the existing paper maps and then perform their vectorization.
Rasta and the CAD
Rasta contains a complete professional CAD, equipped with all drawing functions. It is therefore possible to integrate raster images with vectorial data and then to perform a hybrid print in a single sheet. The CAD supplied with Rasta is equipped with a sophisticated bidirectional interface with AutoCAD which allows both to write and to read DWG/DXF files allowing a complete data interchange with DWG/DXF compatible CAD systems.
Supported formats
Rasta manages a wide range of raster formats both in import and export mode, thus allowing the acquisition of images from various sources: scanner, B/W and color aerial photos, digital cameras, satellite images.
Easy displaying of images
Importing images into Rasta is a very easy procedure. Display, zoom and pan are extremely fast also with big-size images. Rasta allows to display grey-scale, color or monochromatic images of any size and resolution. Monochromatic images can be made “transparent”, to allow a raster on raster superimposition, with the possibility of setting the sequence of the image display and printing. Image management includes specific functions to control contrast and brilliance; for color raster the constant color gamma can be modified.
Georeferencing
Georeferencing allows to obtain a raster image where you can work with real coordinates, take measures, digitize, overlap other images or maps. The georeferenced image can be saved on disk, and then used to produce or update a new cartography, or digitized by CAD functions. Georeferencing functions use the 6-parameters affine transformation and the homographic transformation to remove perspective deformation. Transformations can be performed locally, eliminating anisotropy deformations the sheet or, more in general, the image can have gone through. Control points can be inserted and modified on screen. For map georeferencing some commands exist, for the automatic construction of a control point reference grid.
Perspective rectification
For all those who deal with the architectural restoration of historic centres; it is in fact possible to load the photo of the building facades and perform their perspective rectification so as to draw, by CAD functions, the existing elements of particular interest in a precise scale.
Mosaicing
The georeferencing can be repeated for all the images needed to cover the zone desired; when all the images have been positioned, it is possible to create a new raster grouping together all the images.
Image editing
Rasta possesses different functions which allow to modify both the image geometrical aspect (shape, size) and its visual aspect (color, contrast, brilliance). Some functions are also available, that allow to work on the image deleting or copying both simply and complexely shaped areas inside it.
Digitalizing on video
Loaded images can always be used together with all the drawing functions of graphic CAD; digitizing on video grants more precision because, through zooms on the images, it is possible to observe in a better way the details to be vectorized; images can be made visible or invisible, according to the one’s need.
Vectorization
Images loaded on Rasta can be vectorized automatically allowing to save time during manual digitalization operations; by parameterizing the vectorization algorithm it is possible to obtain good results with any kind of raster.
