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The范特利奥戈翁塞纳克变形金器通过将每个单元格转换为多边形功能来使数据传染数据。这适用于主题映射,因为可以将具有类似值的多边形溶解在一起以产生更大的区域。
TheRasterCellCoercertransformer vectorizes raster data by converting each cell into either a point feature or polygon feature. In point mode, it is more suitable for working with DEM data than for aerial photos or other images as point features can then be used in transformers such as thesurfacemodeller.。在多边形模式下,它类似于梁斯托利堡。
portmoody-clipp.zip.(DEM数据)
rastercoercers.fmwt.(已完成的工作区)
1) Read in a Digital Elevation Model (DEM)
In a blank workspace read in the PortMoody.dem using the加拿大数字海拔数据(CDED)读者。该DEM包含海洋,山脉和城市化区域。
DEM of Port Moody, British Columbia
2) Resample the Raster
Next, add aRasterResampler.transformer. This transformer is used for testing the workspace and can be removed before production if desired. The RasterResampler resamples the raster reducing the size which helps the translation process faster.
在RasterResampler参数中,确保大小规范设置为RowsColumns。对于行和列大小,将使用用户参数来在运行时快速更改单元格大小。单击列旁边的下拉箭头(单元格)>用户参数>创建用户参数。在“添加/编辑用户参数”对话框中设置以下参数:
单击“确定”以创建参数。使用下拉菜单并选择Closeze参数,将参数应用于行数(单元格)。
RasterResAmpler参数,Cellize创建的用户参数。
3) Add the RasterToPolygonCoercer
这个例子将使用多边形,这让年代ense to use the范特利奥戈翁塞纳克transformer instead of the RasterCellCoercer, as it is faster. Add a RasterToPolygonCoercer to the canvas and connect it to the RasterResampler. In the parameters, rename the Label Attribute to _z. The Label Attribute will take the values from the raster bands and convert it to a comma-separated list. This raster only has one band, we will only get one value, which in this case will be the elevation because it is a DEM.
4) Group layers
Merging polygons by their original elevation has the drawback that not many adjacent polygons may have the same values. It would be much more logical - and more in line with a layer-shaded map - to group features at 10ft intervals.
Without grouping the layers, the cells are not related to each other to create elevations. (Viewed by using the Group By option in the Inspector mentioned in Step 5)
To do this, add anExpressionEvaluatorto the canvas and in the parameters set the expression to:
(int((@值(_z)/ 10))))
此表达式将实际高度(_z)划分为十个,将值舍入整数。通过这样做,它有效地在数据上创建了10英尺的高程频段。
5) Inspect output
添加检查器变压器,并将其连接到ExpressioneVulator。在里面Inspector参数,将组设置为_Result。这将为每个_result值设置不同颜色。
Elevations can now be distinguished
6) Dissolve boundaries
Now we can see distinct patterns of elevation, but we can remove the cell boundaries for elevations with the same value. Add a抹布变压器到画布,并使用区域输出端口将其与Inspector之间连接。参数中将组设置为_Result。重新运价翻译以查看高度。
Final workspace
最终输出与细胞边界溶解,细胞大小为100
Try running the workspace with Run with Prompt enabled and set the cell size to different values anywhere between 1 and 1201. A lower cell size will be less detail but will run faster; a higher cell size will have greater detail but will run significantly slower.
A cell size of 50 and a cell size of 1201 set using the CellSize user parameter
TheRasterCellCoercer变压器可以与RastertopolyGonCoercer同样使用,除了它适用于创建点。使用此变压器时协调置换器should be used before the ExpressionEvaulator and Dissolver transformers to extract the elevation from the raster bands.
Data Attribution
Data used in this tutorial originates from open data made available by the Government of Canada. It contains information licensed under theOpen Government Licence - Canada.
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