Image Paint is a set of editing tools that provide the ability to interactively modify the color values of an image or other raster layer, such as a land cover raster. The Image Paint toolset includes operations like Set Color, Heal Color, Fill color, Darken/Lighten, and more.
This tool is similar to the Terrain Painting tool, which works on gridded elevation datasets.
To begin image painting, select the Image Painting button from the Analysis toolbar or the Analysis menu.
| This function requires Global Mapper Professional |
Quick Steps for using the Image Paint tool:
Select the Image Paint tool, then choose the image layer to perform the edits on (if multiple are loaded).
Choose the operation type, then the Brush Color and Brush Type. Adjust brush size and other parameters to match the desired effect. When applicable, the cursor will indicate brush size (red) and distance (blue) that has been set.
Click on the map to perform the edit. When using the line or area brush type, left-click to define vertices, then right-click to complete the shape and apply the edit within that area.
The undo and redo operations can be used throughout the session, including when the tool is closed and reopened. If the workspace has been closed and reopened, it will not be possible to undo edits from the previous session, but the Revert to Original Values brush option will still work.
To move around the dataset while the terrain painting tool is active, click and drag the middle mouse wheel, or use the pan arrow icons at the edge of the map.
Note: Modifications to the image are stored in the workspace. The original file is not directly edited. To create an updated image (as a stand alone file), export the data to a new file.
Note: To use image painting operations on an image loaded from an online dataset, first export the data to a local file and then make edits to the exported copy.
Using the Image Paint tool:
The Image Paint Options dialog will appear while the painting tool is active. This dialog controls the shape and size of the edits applied, as well as what operation is performed in the selected area.
Layer
If multiple Images are loaded, select which image layer to perform the modifications on. Only one image may be edited at a time.
Selected Layer Cell Size will show the resolution or grid cell size for the terrain layer currently being edited. This information can also be found in the layer's Metadata.
Operation:
Fill Color - Replaces all cells in an area that have a similar color with a new color. To use, first set the Brush Color to the desired color, then click on a pixel with the color that will be overwritten. Use the Color Distance slider to specify how similar a color must be to the original in order to be overwritten. A smaller color distance will only flood neighboring cells that are similar or exactly match the selected cell. The little box of color next to the Flood Fill option displays what color will be replaced by the Brush Color, and is updated as you move your cursor over different pixels.
Apply Color - Changes the pixels to the Brush Color as determined by the other brush settings.
Darken / Lighten - Darkens or lightens existing colors in the image. The Color Distance slider determines how light or how dark the applied change is. A larger color distance creates lighter cells. Use the Feathering option to determine how many cells are used to transition between the darkened / lightened cells and the unchanged neighboring cells.
Mark Transparent - Marks pixels as transparent. The resulting display will be either the background color of your workspace (typically white), or any other data loaded underneath the image. The cell will either be set as a no-data value, or the alpha band will be set to 0.
For layer wide transparency options, see Transparency in the Raster Options Display tab.
Heal Color - Replaces the selected pixel values with the average of the neighboring pixel values. This allows users to quickly clean up small mistakes or anomalies by using a majority filter. The number of pixels to be replaced in an area is determined by Brush Size (must be greater than 1 pixel), and the neighborhood size is determined by the Feathering value. When this tool is chosen, the cursor will indicate brush size with a red outline and feathering area with a blue outline.
Replace Color - Changes the selected color to another predefined color for a pixel or selected region. From the Replace Color dropdown menu, choose which color you would like to replace. Use the Brush Color setting to choose a new color to apply. This tool only works on one color at a time. To change multiple colors at once, or to adjust all colors in an image, consider the Raster Reclassification tool.
Revert to Original Values - Reverts the pixels back to original values, undoing any edits made with Image Paint.
Brush Type:
The area that will be edited can be defined by clicking at a point, drawing a line, or drawing an area. The brush type toggles between these different options for selecting the area of the terrain to be edited.
Point - The point brush will apply the specified operation at the clicked location. Note it is necessary to click at each location to apply the edit; click and drag is not implemented.
Line - This brush will apply the operation along a line, with the width based on the brush size and other settings. Left-click to place the first vertex and additional vertices, then right-click to complete the line and apply the edit. Use the undo button to remove the last vertex placement.
Line (Trace Mode) - This brush will automatically trace the operation as the brush moves, applying the changes to the terrain layer when the mouse is released. The line width is based on the brush size and other settings. Hold the left mouse button as you move the cursor across the terrain to draw the operation, then release the mouse to apply it.
Area- Apply the edit operation within a defined area. Left-click on the map to place each of the vertices, then right-click at the last vertex to close the area and apply the edit.
Area (Trace Mode) - This brush can freehand trace an area feature without having to create multiple vertices, similar to a lasso tool. Hold the left mouse button while moving the cursor to draw a line, then release the mouse to automatically close the line into an area feature and apply the operation to the area.
Selected Features - This option allows for a chosen operation to be applied one or more selected vector features simultaneously. Once the features have been selected with the Digitizer tool, the Paint Selected Features button will enable. Click this button to apply the chosen operation to the selected features.
Other Options:
Based on the resampling method set for the raster / image layer, it is not always clear how coarse the image is. The default resampling method is bilinear interpolation, which will smooth the display of the data rather than show the raw pixels. To see the raw pixel values without interpolation, set the resampling method to No Resampling (Nearest Neighbor).
Brush Color - Brush Color will automatically populate with the colors in the image, or you can choose Add New Color.
Brush Size - Specify the brush size in pixels, meters, or feet. The size of the grid cells, or pixels, is explicitly tied to the resolution of the original dataset. To see the resolution of the data, look at Grid Cell Size at the top of the dialog, or go to the layer's metadata.
Color Distance - In the Flood Fill operation, which identifies eligible cells based on cell color similarity, this slider specifies how similar a color must be to the original pixel in order to be overwritten. A smaller color distance will only change cells that have a color that is very similar to the selected pixel.
In the Darken / Lighten operation, a larger color distance creates lighter cells.
Feathering - The feathering effect (available for Set Color, Heal Color, and Darken/Lighten operations) will taper off the edges of the operation. The brush will gradually change the pixels beyond the red circle range to match the values just outside of the feathering zone, shown by the blue circle. This is similar to Feathering Tab options, but occurs only in the local area where the edit was made.