ProRaster Help – Preview Map Window

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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The ProRaster User Guide is available for download as a PDF.

Working with the Preview Map

 If your algorithm is valid, then it will be rendered in the preview map window. An algorithm can be invalid for a variety of reasons: 

  • The algorithm is disabled, or all layers are disabled, or there are no layers defined, or all components in layers are disabled.
  • You have a component enabled but a raster source has not been selected for that component.
  • You have a raster source selected for a component, but the raster could not be loaded. In this case the Field and Band drop-lists will be empty.
  • You have not defined a data-color transform for an enabled Color, Red, Green, Blue, or Opacity component.
  • Raster data cannot be reprojected into the algorithm coordinate system.
  • Raster data, when reprojected into the algorithm coordinate system, is outside the allowable data range of that coordinate system. 

The most difficult problems to diagnose are with coordinate systems. For example, imagine you have a LUT Color layer with color drawn from a projected coordinate system (like UTM) and you have a global raster in a geodetic coordinate system in the intensity component. The system determines that the algorithm coordinate system is projected, and it attempts to compute the algorithm data range by converting the range of the global geodetic raster to projected coordinates. These coordinates are likely to be invalid and this causes a rendering failure. In a situation like this you can use the “Zoom to selected extent” button to zoom to the bounds of a coordinate system, the extents of a raster source, or to a manual geodetic coordinate range.

Zooming and Panning

In the map window, use the mouse to zoom and pan. Roll the mouse wheel to zoom in and out about the location of the cursor. There is a natural limit to how far you can zoom out and once you reach this limit the map will fit to the algorithm extents. You can force the map to fit to the algorithm extents and redraw by hitting the “Zoom to algorithm extents” button. Pan the map by holding down the left mouse button and dragging. 

Sometimes the algorithm properties (reflected in the dialog and property pages) can get out of sync with the rendered preview. You can resolve the issue by hitting the “Zoom to algorithm extents” button, which also causes the algorithm to reset and reload. 

Also, it is possible that the status of a layer or component (enabled or disabled) reflected in the algorithm tree control can get out of sync with the same property in the property pages. To resolve this, set and reset the Enable property in the property pages and the tree, properties and preview should all come back into sync. 

You can collapse the preview map window by clicking the “Close preview window” button. Once it is collapsed (and depending on your product tier) you can hit the “Open preview window” button to restore it, or you can hit the “Open a floating map” button to open an undocked and resizable map window. You may be able to open multiple undocked map windows. To close all undocked map windows, simply hit the “Open preview window” button. To control whether the ProRaster dialog stays on top of the map windows, see the Options dialog. 

Drop down the “zoom to selected extent” menu button for more zoom options. You will be able to zoom to the bounds of any coordinate systems used in the algorithm (if those bounds are known). You will be able to zoom to the extents of any raster source used in the algorithm. You can also select the “Zoom manually” option to open a zoom dialog in which you can specify a zoom rectangle in WGS84 longitude and latitude coordinates.

These zoom options are provided both for convenience, and for recovering control of the map window when the true extents of the algorithm cannot be computed. This can occur when the extents of a raster source are outside of the bounds of a coordinate system that those extents must be converted into. This conversion will often fail and return invalid coordinates, and this will cause the map to fail to render. Zooming to a valid extent for the algorithm coordinate system can recover the map window.


 As you move the mouse cursor about in a map window, ProRaster can report the raster value at that location as a tooltip. Drop down the “Tooltip reporting mode” menu button to control the amount of information displayed – No tooltip, Key Data Value, Key Data Information, or All Data Information. 

  • No tooltip

 No tooltip is displayed as you move the mouse cursor over the preview map or external map window. 

  • Key Data Value 

The key value is the value of the raster at the cursor location in the primary component of the layer. If there are multiple layers then the value of the first layer, from the top down, to provide a valid value at the cursor location is reported. The primary component is generally the color component, but if color is disabled it will be the intensity component. 

  • Key Data Information 

In this mode we report the key value, but also report the raster, field, and band from which that data was acquired. The location of the cursor is also reported. 

  • All Data Information 

This is a verbose reporting mode that you would only use sparingly. We report the all the raster values, as well as the raster, field, and band from which that data was acquired. The location of the cursor is also reported. 

You can also toggle the “Show geodetic coordinates” switch. When enabled, this will convert the mouse cursor coordinates from the coordinate system of the algorithm to WGS84 longitude & latitude geodetic coordinates. 

To acquire a complete report on all the raster data at the cursor location, double click. A report will be displayed in the algorithm property sheet, on a property page labelled “Report”. This property page is automatically selected for your convenience. 

The report is in XML, and you can copy-and-paste it into an editor of your choice. In the report you will find the exact location of the cursor and the coordinate system of the reported coordinates. It will then provide hit-testing information on every raster intercepted at that coordinate. These are reported from the top down (i.e., last rendered to first rendered). 

There are two possibilities when reporting raster data at a location: 

  1. You can report the cell value, at base level resolution, with or without interpolation.
  2. You can report the actual cell value used in the rendering engine, derived from an appropriate resolution level, probably acquired by interpolation (it depends on the interpolation properties in the algorithm). 

ProRaster reports data type (2) – the actual data value used in the rendering engine. This means the point must have a scale. For each raster intercepted we report the coordinate range of the pixel that has been targeted, as well as the cell value of that pixel. 

If the raster is a virtual raster (MVR) or a rendering algorithm (MRD) then the report will drill down into the source rasters that those virtual rasters depend upon. In this case, you will see the value of the virtual raster reported, and then the values of the source rasters reported. As virtual rasters can contain other virtual rasters, these chains can become quite deep.