Map Tools
On this page, you will find general help for the ProRaster product family including links to documentation, instructional videos, and training videos.
Previous Topic: Concepts, Terms, and Outcomes
Next Topic: 3D Maps
Back to: ProRaster Scientific Help
Back to: ProRaster Help
Back to: ProRaster
Go to: ProRaster Essential help page, ProRaster Premium help page, ProRaster Scientific help page.
The ProRaster User Guide is available for download as a PDF.
Distance Tool
The distance tool provides a mechanism to measure the distance between two points on a map, or along a multi-point polyline on a map.
Access the distance tool by right-clicking on a map and selecting the “Distance” option from the context menu. To specify a line, left click and hold, drag, then release. As you are dragging a line will be displayed in the map and a floating tooltip will show the distance along the line. A report is also generated and displayed on the Report property page of the algorithm. To measure another distance, simply repeat and the current distance trace will be replaced.
The “Straight Line” distance is the distance between the end points of the line, measured in the units of the map coordinate system. If you are using a geographic coordinate system this distance will be in “degrees” and may not be very useful. In a projected coordinate system, it is likely to be in metres or feet.
The “Great Circle” distance is the distance along the great circle joining the end points of the line and is reported in metric units. This is only reported if map coordinates can be converted to geographic coordinates (longitudes and latitudes). The great circle distance is computed using the Haversine formula for an Earth of radius 6371km.
To define a multi-point polyline, left click and release, then move to the next desired point and left click and release again. Repeat until you reach the final desired point, then left double click to end the polyline. The distance reported will be the cumulative distance along each line segment of the polyline.
When defining a distance trace, you can use the mouse wheel to zoom in and out without terminating the trace. If you approach the edge of the map, the map will automatically be scrolled to keep the end point of the trace within the map. Whilst in distance tool mode, you can pan the map by holding the CTRL key, left click and hold then drag. To turn off the distance tool, right click to display the map context menu and select any other tool.
Area Tool
The area tool provides a mechanism to measure the area of a polygon drawn on the map.
Access the area tool by right-clicking on a map and selecting the “Area” option from the context menu. To define a multi-point polygon, left click and release, then move to the next desired point and left click and release again. Repeat until you reach the final desired point, then left double click to end the polygon. The area of the polygon will then be computed and displayed in a report on the Report property page of the algorithm. To measure another area, simply repeat and the current are polygon will be replaced.
The ”Map Area” is the area of the polygon computed from map coordinates and is expressed in the units of the coordinate system. If you are using a geographic coordinate system the units will be degrees and of little value. If you are using a projected coordinate system, you ought to consider whether it is suitable for area calculations.
The “Spherical Earth Area” is the area of the polygon on a perfect sphere with the Earths radius. It is computed using line integrals and Greens theorem. You can convert this area to the area on any spherical body by dividing by the Earths radius squared and multiplying by the required radius squared. We use a radius of 6371000 metres and the area is reported in square metres.
The “Transformed Area” is the area of the polygon computed after transformation to a suitable equal area projection. We use a Lambert Azimuthal Equal Area projection that is centred on the centre of the polygon and the area is reported in square metres.
When defining a polygon, you can use the mouse wheel to zoom in and out without terminating the polygon. If you approach the edge of the map, the map will automatically be scrolled to keep the end point of the polygon within the map. Whilst in area tool mode, you can pan the map by holding the CTRL key, left click and hold then drag. To turn off the area tool, right click to display the map context menu and select any other tool.
Profile Tool
The profile tool provides a mechanism to extract raster data along a profile trace and display it in the map as a transparent overlay in real time. The profile trace can be defined by two points on a map, or as a multi-point polyline on a map. The example below shows a profile across Mount Kilimanjaro. The imagery has been made semi-transparent to highlight the profile trace and profile section.
Access the profile tool by right-clicking on a map and hovering over the “Profile” option on the context menu. Then select either “Single Profile” or “Stacked Profile”. If you choose single profile, then each profile trace you define will replace the previous one and only one profile section is ever displayed. If you choose stacked profile, then each profile trace you define is added to the profile section and multiple curves are displayed.
To specify a profile trace, left click and hold, drag, then release. As you are dragging a line will be displayed in the map. When you release, the profile section is displayed, and a comprehensive report is generated and displayed on the Report property page of the algorithm.
To define a multi-point polyline, left click and release, then move to the next desired point and left click and release again. Repeat until you reach the final desired point, then left double click to end the polyline.
When defining a profile trace, you can use the mouse wheel to zoom in and out without terminating the trace. If you approach the edge of the map, the map will automatically be scrolled to keep the end point of the trace within the map. Whilst in profile tool mode, you can pan the map by holding the CTRL key, left click and hold then drag. To turn off the profile tool, right click to display the map context menu and select any other tool. To remove the current profile or profiles, you can select “Clear Profiles” from the map menu.
You can define a profile at any scale for a source raster of any size. ProRaster will always acquire data from the source raster at an appropriate resolution and spacing ensuring you always see the highest quality section data.
You can control which raster is used as the source raster by selecting the raster in the algorithm tree control. If you have multiple layers or multiple rasters contributing to the algorithm, it is important to select the layer or component which is using the raster you want to target prior to entering Profile mode. If you want to change the source raster, clear the profiles then select the appropriate layer or component in the algorithm tree, then select the required profile mode again. You can check that the correct source raster is being used by examining the report.
The profile window will be displayed semi-transparently over the top of the map. The primary feature is the profile section. This is usually a continuous curve but if the profile trace crosses an area of the source raster that contains no data, then the curve will be broken. On the left side is displayed the minimum and maximum value of the profile data. For example, if you are drawing profiles across a terrain raster these will reflect the minimum and maximum DTM values along the profile trace. If the units of the data are known, they will be displayed. In the top right corner, the data range is displayed. This is simply the maximum – minimum. In the bottom right corner, the distance along the profile trace is displayed. Where possible, this will be the cumulative great circle distance. Otherwise, it will be the cumulative map distance (see the Distance tool for an explanation). Take note of the units which change according to the scale.
The profile is drawn left to right in the direction in which the profile trace was defined. The only time this may not be true is when you are using a Projected horizontal axis and there are multiple profiles.
From the Profile context menu, you can access a Profile Settings dialog. Here, you can define the position and size of the profile window on the map. You can locate it in any corner of the map, and it can extend to the full width of the map and up to half the height of the map. Changes are applied immediately.
In the main application Options dialog, there is an option called the “Pixel Scaling Factor”. You can use this to adjust rendered items that are measured in pixel units. This includes line thicknesses and text size. For example, if you have a very high resolution monitor you might set a factor of 2.0 to increase the size of text and thickness of lines. Or, if you like finer features, you can set a factor of 0.8 to slim these rendered items down.
You can control the horizontal axis measure and the vertical axis scaling. By default, the horizontal axis uses the distance along the profile trace. If possible, this will be a great circle distance, and otherwise it will be a straight-line distance in horizontal map units. When displaying multiple profiles (stacked profiles), all the profiles are anchored to the left at zero distance.
The “Projected” option for the horizontal axis allows you to line up multiple profiles over a feature in a more appropriate way. When selected, all the profiles are projected onto a common straight line that is chosen as the best fit to all the contributing profiles. In the settings dialog you can select “Show the projection system”. You will now see the bounding box of the projected distance coordinate system and the common baseline drawn very faintly.
By default, the profile data is scaled vertically so that the range fits to the section box. You can choose to scale the data so that there is no vertical exaggeration or define a specific level of vertical exaggeration. In the “Vertical Axis Scaling” section, select the “Scaled” option and set the scale factor to 1.0. If the horizontal units match the vertical units, then the profile section will now be plotted at “true scale”. It is important to consider the units if they are different. If ProRaster knows the vertical units then they will be displayed and they will be used to adjust the scaling appropriately. If they are not displayed you will have to use the scaling factor to adjust for the differences in units, and to apply any desired exaggeration.
The example below shows multiple profiles across Mount Kilimanjaro. The horizontal axis using projection, so all the profiles line up appropriately regardless of the length of the profiles or the orientation. Note that each profile has an individual color that is automatically assigned.
The profile report will look like the example shown below. Note that the report is based on a single profile. If you are drawing multiple profiles then it will be for the last profile you drew.
Profile Report for MERIT_DEM.mrr
Field [0] Band [0] Time [-9223372036854775808,9223372036854775807]
Map Distance [55.19648393 kilometers]
Earth Distance [55.05374229 kilometers]
Minimum [1021.612004] Maximum [5790.419866] Range [4768.807862]
Mean [2664.179701] Median [2337.536419] Mode [1253.290315]
Standard deviation [1341.294892] Skewness [0.7286764459]
Total ascent [4873.004325] over [28.35881983 kilometers]
Minimum ascent angle [0.04656774264] Maximum [47.19184489]
Mean ascent angle [9.286182561] Median [5.473275009] Mode [2.051178473]
Number of ascents [10]
Ascent length minimum [185.3454385] maximum [8711.953455] mean [2835.881983] median [2224.086307] mode [463.3652626]
Total ascent minimum [0.150662668] maximum [2210.617151] mean [487.3004325] median [82.36038109] mode [57.69746556]
Total descent [4175.651106] over [26.69492245 kilometers]
Minimum descent angle [0.06869424795] Maximum [28.34153514]
Mean descent angle [8.745426688] Median [7.604932721] Mode [8.431478544]
Number of descents [10]
Descent length minimum [185.3452002] maximum [23358.59842] mean [2669.492245] median [494.3110849] mode [463.4144965]
Total descent minimum [0.2222186011] maximum [3968.937207] mean [417.5651106] median [57.13659704] mode [51.4451592]
It reports the source raster name as well as the field and band indices, and time range for which the data was acquired. The Map distance is the cumulative distance along the profile trace in the units of the map coordinate system. The Earth distance, if reported, is the cumulative great circle distance along the profile trace (from each point to the next). It then reports summary statistics of the profile data.
It then reports statistics that are of interest to users examining terrain data. It reports the total height ascended, and the distance over which you were ascending. Summary statistics for the angle of ascent (in degrees) are then reported. It reports the number of ascents you will make and then summary statistics for the length of the ascents. Finally, it reports summary statistics for the height of all ascents. The same statistics are then reported for all descents.
Swapping
Swapping takes advantage of graphics hardware acceleration to instantly swap between layers or groups of layers, allowing you to visualise changes between layers. When you swap, the spatial extents of the map are not changed, so you can compare spatially overlapping data.
If you have a rendering algorithm with multiple layers or multiple groups, then you can activate swapping in a map by right-clicking to access the map menu, hovering over “Swapping” and selecting a swapping method. The method chosen will determine how the transition between layers occur. “Flip” swaps instantly. “Fade” swaps by fading the current layer out whilst fading the next layer in. “Slide” allows you to interactively slide a curtain left and right. “Scroll” allows you to interactively raise and lower a curtain.
When you activate swapping, each layer in the algorithm will be rendered to a different graphical “plane” so that the system can quickly display one or the other. There may be a delay whilst the algorithm is rendered. Once you have finished, you ought to disable swapping to return to the normal rendering mode.
If you have multiple groups of layers, you can choose to swap by group. In this case each time you swap all the layers in the group will be displayed. This is controlled via a toggle on the map menu – “Swapping Layers” or “Swapping Groups”.
When flipping or fading, hit the LEFT and RIGHT arrow keys to move to the previous or next layer or group. You can also hit the UP and DOWN arrow keys to move to the top or bottom layer or group. Note that groups or layers that are not enabled for display will not be displayed when swapping.
When sliding or scrolling, the handle will only be displayed when you hover the cursor over it. Move the cursor over the map and left click on the circular handle when it is displayed. Left click and drag to drag the curtain.
Swapping works in Preview and External map windows. However, when swapping in the Preview window the arrow key presses are sometimes not detected. It helps to move the mouse in the preview map window to ensure that arrow key hits are directed correctly.
To swap algorithms, you can take advantage of the fact that an MRD file (rendering algorithm) can be loaded into another rendering algorithm and treated as though it is a raster. Create each algorithm you want to swap and save them to separate files. Now create a new algorithm and load each of the MRD files into a separate layer. They will be displayed using Image layers. Make sure you choose an appropriate coordinate system for the algorithm. You can then activate swapping for the layers.