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drcorrell

Clipping Plan Map

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I have created several plan maps that contour PCE concentration in groundwater at a site. The high concentration in several wells(9000 ug/L) causes me to set the contour intervals at 500. I then set the lower limit at 1 but the map then shows some of the lower concentration wells (between 1-500ug/L) as having no concentration. I would like to clip out the outer edges with a polygon so I can get rid of all the pink color outside the well field. Is there a way to clip using a polygon? I have attached the plan map. Thank you in advance for any assistance you can give me.

post-9854-068664200 1285788335_thumb.jpg

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You can use the Utilities Grid | Filters | Polygon Clip to filter each of the GRD files you've created (in the Plan Map tool), to set the nodes outside the well field polygon to null. The null areas will not be displayed with any color.

Defining the polygon: In RockWorks15 you can draw the polygon right onto an existing map, right click on it, and save the polygon vertices to a Polygon Table in the project database; then use that polygon to clip the grids. Of course, you can also simply hand-type the vertices into the Polygon Table.

Another helpful tool for maps with wide value ranges is to define a Color Fill Table with the desired colors for specific value ranges - you can make these as detailed as you like, even use a logarithmic-based color scheme.

Feel free to contact [email protected] if you have additional data- or project-specific questions.

Molly Mayfield

RockWare Inc.

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I use Esri Arcmap to visualize maps created by either RockWorks15 and Surfer.

To get the clipping polygon vertices I convert the shape features (polyline), defined with the editing function in Arcmap with snapping option activated, to points by mean of a free scripts downloaded from Esri website, get the point XY coordinates and save them to txt table. In RockWorks15 I import the table to get the vertices coordinates.

Defining the polygon: In RockWorks15 you can draw the polygon right onto an existing map, right click on it, and save the polygon vertices to a Polygon Table in the project database; then use that polygon to clip the grids. Of course, you can also simply hand-type the vertices into the Polygon Table.

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You can't crop a map with a polygon (in RockPlot2D) but you can clip the grid model from which the contours were drawn. Use the Grid | Filters | Polygon Clip to clip the grid model (assigning null values for nodes outside the polygon), then create a new map for the clipped grid. The contours won't draw outside the polygon.

Molly Mayfield

RockWare Inc

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You need to be sure that the nodes outside the polygon are not set to zero (resulting in steep contours) but instead to null. This assignment is defined in the "new exterior value" prompt in the Grid Polygon Filter options window. When you click on that option, you can either type in a value or click the Null button.

Molly Mayfield

RockWare Inc.

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