Introduction
The construction of outer limits is (obviously) a complex operation. Sometimes it is best to do this area by area and in multiple steps, then combining points into one or more final outer limits. Sometimes the outer limit line may be constructed from a combined formula line and a combined constraint line.
The ultimate construction may still be a complex logical and strategical operation. The Geocap Final Outer Limit tool is designed to digitize to combine line segments and keep distances between points less than 60M.
Exercises
About the Outer Limit Menu
The "Outer Limit Menu" is used in order to select the final outer limit points from the formula and constraint lines. You may open the outer limit menu by right-clicking on the project folder 4. Outer limit and selecting Generate Outer Limit.
The Outer Limit Menu
The blue question mark in the top right corner of this menu contains instructions on how to use this menu.
The folders in the Outer Limit menu correspond to the sub folders in 4. Outer limit. You will also be able to see the datasets in this list. Before opening this menu, you can copy the files you want to use in your outer limit to the correct folders.
You can display the different data sets by checking the data sets you want to display, and clicking the pencil. Multiple select is allowed in this list. You can scale the display window to the data sets the same way by checking the datasets, and clicking the scale button.
The digitize button is used to digitize points from the checked data-sets. You can use this to pick points on your final outer limit. Each time you pick a point, a white circle of 60M will be displayed around the last picked point. The circle is geodetic correct. This will be a guide to you when digitizing the final outer limit. The distance between the final outer limit points should be less than 60M, so the next point you pick should be inside the circle.
Try the Outer Limit tool
Before doing the exercise below, get a hand on feeling with the functionality of the digitizer, just by playing around with two datasets.
- Copy the 200M line into 4. Outer limit / Formulae
- Copy your 2500m + 100M into 4. Outer limit / Constraints
- Display the data from the Final Outer Limits panel. Note that the data may also be displayed from the project, e.g. Display Points.
- Try the various digitizing operations.
Generate the Outer Limit
In this exercise we are going to digitize the outer limit from your formula, and constraint lines using the Outer Limit menu.
- Copy all your formula lines to the 4. Outer limit / Formulae folder (200M, FOS+60, Sed>1% points)
- Copy all your constraint lines to the 4. Outer limit / Constraints folder (350M, 2500m + 100M)
- Open the Outer limit menu, and check some of the datasets and use the Display and scale buttons
The Outer Limit menu with Datasets Copied
- Digitize a combined formula line, by clicking the digitize button and following the instructions
- When you have finished digitizing and clicked the end digitize button, give the new dataset a name, such as combined formula line.
- Right click the new line in the project, and select Table view
- Observe the new columns in the table
There are also two tools which have been developed in order to Optimize the outer limit and to Maximize the outer limit. These tools should be used with great care in order for them to be utilized correctly. It cannot be assumed these tools will automatically produce the absolute maximum achievable area. They are interactive tools that should be experimented with, using different settings until the desired result is obtained.