#Mapublisher graticule add n how to

If there are any lingering polar points, you can delete them from the horizon line manually using the Direct Selection Tool. Once the custom Orthographic coordinate system is created, complete the MAP View transformation. Choose the Orthographic, meter projection, click Copy Object to begin editing the coordinate system and put in the custom central meridian and latitude of origin you chose back at the beginning of the workflow. Use the Crop to Shape tool to remove the features outside of the polygon.Īfter cropping, go to the MAP View and Perform Coordinate System Transformation. Export the polygon area in case you need to add additional data at a later date. Continue using the Pen Tool to close the polygon by following along the edge of the artboard (result should look similar to the image below). Use Illustrator’s Pen Tool rejoin the two lines into one. Resize the artboard to match the extents of the WGS84 MAP View. Move the section of the curve remaining outside the artboard inside and to the opposite edge. Next, use Illustrator’s Scissors Tool to cut the polyline at the artboard edge Use Illustrator’s Direct Selection Tool to select and delete the horizontal portion of the horizon polygon. You can also hide or remove the Lambert Azimuthal Equidistant MAP View. If necessary, transform it to WGS84 and drag your horizon line into this MAP View. Step 5: Back to WGS84 and Editing the Horizon line We can first determine the circumference by: = 2πr = 2 × π × 6,371,007 = 40,010,000 m Now that we know Earth’s circumference, we can determine the distance to the horizon by: = C × 1/4 = 40,010,000 × 1/4 = 10,002,500 m or 10,002.5 kmĬonvert the resulting circle with four Bezier curve points to polylines using MAPublisher’s path utilities tool Convert Beziers to polylines. Next, add a buffer of 10,002.5 km (see note below) around your focal point.Ĭurious about where the buffer value comes from? Given that we know: Earth’s radius using Authalic Sphere is 6,371,007m The formula for the circumference of a sphere = 2πr The distance from the focal point to the horizon in the Azimuthal Equidistant projection = 1/4 of Earth’s circumference = C × 1/4 Click OK and apply the projection.Ĭreate the horizon line from your custom centre point. You may rename the custom projection on the Identification tab if you wish to reuse it later. Next On the Definition tab, set the Central Meridian to 100, and the Latitude of Origin to 70. The other version of the projection uses an ellipsoid datum which would require more complex formulas to solve the buffer distance in Step 3. Furthermore, you must use the ‘Sphere’ version of the Lambert Azimuthal Equidistant projection, because the radius is equal in all directions. Side Note – Why start with the Azimuthal Equidistant projection? The straight-line distance between the central point on the map to any other point is the same as the straight-line distance between the two points along the earth’s surface. Under the Projected > World category, find Lambert Azimuthal Equidistant (Sphere), meter and click the Copy Object button to begin editing a copy of the existing Lambert Azimuthal Equidistant (Sphere), meter coordinate system. Enable Perform Coordinate System Transformation and click the No Coordinate System Specified hyperlink. To do so, go to the MAP Views panel > Edit Map View. Reproject the map to Azimuthal Equidistant (with a sphere-based datum). Step 2: Project to Azimuthal Equidistant Projection Create a point layer, and plot your centre point using the MAP Point Plotter tool. In this example, our focal point is 70°N, 100☎. Next, decide where you want the final orthographic map to be focused on. Import your world dataset and ensure the MAP View is in WGS84 (or you can use the world.mif file from the MAPublisher Tutorial Data folder). It can be easily adapted for any orthographic projection with a custom latitude of origin and/or central meridian.

#Mapublisher graticule add n how to

The following workflow is one example of how to overcome this limitation. In order to prevent these inaccuracies, we need to remove the data beyond the horizon before transforming the data to the Orthographic projection. This can create a “hollow Earth” or see-through effect that would cause confusion to the map reader.įurther confusion may arise depending on the order of the artwork within the layers, as some features that should be on the far side of the Earth may appear on top of features on the near side of the Earth.

However, when MAPublisher displays the world in the Orthographic projection, it will still draw any points, lines or polygons that fall beyond the perspective’s horizon.

# Not run: library ( rgdal ) x <- as.matrix ( expand.The Orthographic projection is a commonly used projection by cartographers because it closely resembles the world as we know it exists.