11/29/2023 0 Comments Raster format in gis![]() ![]() Raster data to polyline features using the Raster To Polyline tool.If the cell size is 1 meter, the road would be 1 meter wide. Obviously, a road is not 1 kilometer wide thus, you should choose a cell size that is appropriate to the linear feature that you are representing. For example, if the linear features that are being converted represent roads and the cell size is 1 kilometer, the road will be 1 kilometer wide in the output raster dataset. If multiple lines pass through a single cell, ArcGIS will randomly select one of the lines to use to represent that cell location in the output raster dataset.Īs with point data, linear features will become the width of the cell. For any line that passes within the extent of a cell, that cell will receive the value of the attribute identified in the conversion. When there is a break between the chain of same-valued cells, it represents a break in the line feature, which could represent different features such as two roads or two rivers that do not intersect.Ĭonverting linear data to a raster dataset is similar to converting point data to a raster. In vector format, a line is an ordered list of x,y coordinates, but in raster format, it is represented as a chain of spatially connected cells with the same value. Point features to raster data using the Point To Raster tool or Feature To Raster tool.Raster data to point features using the Raster To Point tool.You should make your cell size small enough to capture sufficient input points for the desired analysis. Thus, you should choose a cell size appropriate to the feature that the point represents. Point data features will become the size of the cell. It is possible to have fewer cells with values than there are points being converted. However, when using the Point To Raster tool, you can choose the type of cell value assignment. In general, if two or more points fall within the extent of a cell, ArcGIS randomly selects one of the points when assigning a value to the cell. With a cell representation of point data, there is some generalization of the original data. For example, it is assumed that a well, a telephone pole, or the location of an endangered plant occupies the entire area covered by a cell. Therefore, the smaller the cell size, the smaller the area and, thus, the closer the representation of the point feature. By definition, a point has no area but is converted to a cell representing area. PointsĪ point is represented by an explicit x,y coordinate in vector format, but as a raster, it is represented as a single cell-the smallest unit of a raster. Raster data is best used when your primary concern is with the locational relationships of the phenomena represented by geographic features and not the features themselves. As a result, when representing geographic features in a raster dataset, they become collections of cells with the same attribute values but lose their unique identities. In raster data, the cell typically represents the predominant feature or phenomenon of the area covered by a cell, whereas vector data can accurately delineate or identify individual features. ![]()
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