ProRaster Help – Contour Labels
On this page, you will find general help for the ProRaster product family including links to documentation, instructional videos, and training videos.
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On the “Labels” property page you can enable labelling on major contour lines and control the appearance and frequency of those labels.
Define the font size (height) in pixels. This font size will be multiplied by the “Pixel Scaling Factor” defined in the ProRaster Options dialog.
Also define the label density – ranging from 1 (minimum density) to 100 (maximum density). This will modify how many labels are rendered along the contours.
Labels will be rotated to match the contour line direction, but you can improve the readability of the labels by checking the “Upward reading text” option to make sure that labels are always forward reading and upright.
Check the “Match line color” option to set the label color to the line color, whatever that is (it may be a minor or major line color or derived from color modulation). Alternatively, you can define the label color and opacity.
If these options do not provide you with the flexibility you require, you can specify all contour line properties manually. On the “Levels” property page, check the “Manual Contour Levels” option and browse to the CSV file you have prepared containing the contour information. The CSV file format ought to match the following example –
Level,Major,Width,Color,Label,FontSize,LabelColor
8027,true,2.0,”RGBA(0,0,0,255)”,”Shishapangma – 26,335ft”,14,”RGBA(0,0,0,255)”
8035,true,2.0,”RGBA(0,0,0,255)”,”Gasherbrum II – 26,362ft”,14,”RGBA(0,0,0,255)”
8051,true,2.0,”RGBA(0,0,0,255)”,”Broad Peak – 26,414ft”,14,”RGBA(0,0,0,255)”
8080,true,2.0,”RGBA(0,0,0,255)”,”Gasherbrum I – 26,509ft”,14,”RGBA(0,0,0,255)”
8091,true,2.0,”RGBA(0,0,0,255)”,”Annapurna I – 26,545ft”,14,”RGBA(0,255,0,255)”
8126,true,2.0,”RGBA(0,0,0,255)”,”Nanga Parbat – 26,660ft”,14,”RGBA(0,0,0,255)”
8163,true,2.0,”RGBA(0,0,0,255)”,”Manaslu – 26,781ft”,14,”RGBA(0,0,0,255)”
8167,true,2.0,”RGBA(0,0,0,255)”,”Dhaulagiri I – 26,795ft”,14,”RGBA(0,0,0,255)”
8188,true,2.0,”RGBA(0,0,0,255)”,”Cho Oyu – 26,864ft”,14,”RGBA(0,0,0,255)”
8485,true,2.0,”RGBA(0,0,0,255)”,”Makalu – 27,838ft”,18,”RGBA(0,0,255,255)”
8516,true,2.0,”RGBA(0,0,0,255)”,”Lhotse – 27,940ft”,10,”RGBA(0,0,0,255)”
8586,true,2.0,”RGBA(0,0,0,255)”,”Kangchenjunga – 28,169ft”,14,”RGBA(0,0,0,255)”
8611,true,2.0,”RGBA(0,0,0,255)”,”K2 – 28,251ft”,14,”RGBA(0,0,0,255)”
8848,true,2.0,”RGBA(0,0,0,255)”,”Mount Everest – 29,031ft”,14,”RGBA(0,0,0,255)”
The CSV file ought to have 7 comma delimited columns and always include a header line (although the names of the columns is not important). Specify the contour level, whether the line is minor (false) or major (true), the pixel width of the line, the color and opacity of the line as an “RGBA(red,green,blue,opacity)” string where all color components have values from 0 to 255, the label string, the font size in pixels, and the label color and opacity. The manual option still allows you to control minor line dropout and most of the label properties remain editable. Choose a base font size that is similar to the font sizes you specify in the CSV file (they will be scaled). You can control label density and other appearance overrides.
The “Adjust Resolution” option is on the Contour Component property page. This is usually set to zero for imagery layers, but by default it is set to 2 for contour layers. When it is set to zero, we acquire raster data at a resolution matching the screen pixel size. For imagery, this ensures that you are always rendering raster data at the highest and most appropriate resolution. But when we contour, we do not generate pixels – we generate line segments. To generate a line segment per-pixel is possible, but arguably unnecessary and inappropriate. For each step of the “Adjust Resolution” setting above 0, we reduce the resolution by a factor of 2. This reduces the amount of data to contour by 4. At the default value of 2, we have reduced the amount of data by 16 and are generating line segments that are 4 pixels long on average.