Manifold provides a list of Favorite Coordinate Systems in coordinate system dialogs. We can pick a Favorite with a single click. By default, two coordinate systems, Pseudo-Mercator and Latitude / Longitude, are listed as Favorites. We can add other coordinate systems as Favorites, so they too will appear in the Favorites list. That is a great way of providing access to frequently-used coordinate systems with a single click, for example, perhaps a local coordinate system used for most of our work in our town or region.
Although Manifold Viewer
is read-only when it comes to saving projects or writing to databases
and linked files, Viewer can
update Favorites and have those updates available in future Viewer sessions.
That is a great way for Viewer users to save frequently-used coordinate
systems.
To add, delete, or modify favorite coordinate systems, first click the coordinate picker button in the Reproject Component,
Assign Initial Coordinate System, or Repair Initial Coordinate System dialog.
The resulting menu presents a
list of favorites, with Pseudo-Mercator and Latitude / Longitude being
built-in favorites, and the option to choose Favorites.
The Favorites dialog for coordinate
systems allows building and editing a list of frequently used coordinate
systems. Any favorites we add will appear in the pull down lists
of favorites in menus to pick coordinate systems, allowing a one-click
choice of a favorite.
|
Add - Add a new favorite. Launches the Coordinate System dialog. |
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Add Defaults - Adds factory default favorite coordinate systems to the current list. Use this to restore factory settings if any of the original default favorites have been deleted. |
Ctrl-click |
Ctrl-click a favorite to select it or to de-select it. |
Ctrl-A |
Select all favorites. |
Ctrl-I |
Invert the selection. A quick way to select none is to Ctrl-A and then Ctrl-I. |
|
Move to Top - Moves the selected entries to the top of the list. The entry must be selected for this button to be enabled. |
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Move Up - Moves the selected entries up one position in the list. The entry must be selected for this button to be enabled. |
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Move Down - Moves the selected entries down one position in the list. The entry must be selected for this button to be enabled. |
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Move to Bottom - Moves the selected entries to the bottom of the list. The entry must be selected for this button to be enabled. |
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Delete - Remove the selected entries from the list. The entry must be selected for this button to be enabled. |
keep metrics / override metrics |
Choose whether this Favorite overrides existing Coordinate System Metrics when re-projecting, or if it keeps whatever existing metrics are currently in use.
keep metrics is the default. When we switch the setting to override metrics, in addition to showing that in the Favorites dialog the name of the coordinate system in the list shown in drop down menus will have a # character added, to indicate that coordinate system will override metrics when applied. |
Add to Favorites |
Enabled when the lower pane contains a coordinate system and that coordinate system is selected (shown with red selection background color). Ctrl-click the coordinate system to select it. Pressing the Add to Favorites button will add it to the Favorites list.
Choosing a coordinate system through other means and then launching the Favorites dialog will populate the lower pane with that coordinate system. |
Coordinate system dialogs called by the coordinate system picker button in the Info pane will feature favorite coordinate systems in menus.
We click the coordinate system picker
button.
Clicking the coordinate system picker button in the Reproject Component dialog will launch a context menu that allows us to choose a new coordinate system. Favorite coordinate systems will appear in a list, along with an More... option to launch the full Coordinate System dialog, and a Favorites choice to launch the Favorites dialog.
Clicking one of the listed favorites will immediately choose that coordinate system, for example, the Pseudo-Mercator favorite shown in the illustration above.
We have the focus on a layer that uses a Universal Transverse Mercator - Zone 10 (N) coordinate system, and we would like to add that coordinate system to our Favorites list.
In the Info pane, we click the
coordinate system picker button and choose Reproject
Component. That launches the Reproject Component
dialog. We click the coordinate system picker button in the Reproject
Component dialog to launch a context menu.
We choose Favorites in the context menu.
The Universal Transverse Mercator - Zone 10 (N) system appears in the lower panel since it is the current system in use. Ctrl-clicking the system selects it, showing it in red selection background color.
Pressing Add to Favorites will add the selected coordinate system to the favorites list.
The Universal Transverse Mercator - Zone 10 (N) coordinate system is added to the favorites list. It is selected, so we can move it up in the list or delete it. We can double-click the name to change the name, or we can double-click the keep metrics cell to change that setting.
We double-click the keep metrics cell.
In the drop down menu we choose override metrics.
We press OK to commit the changes and to add the new Favorite.
We click the coordinate system picker
button.
The next time we click into a dialog that shows the Favorites list, we will see a Universal Transverse Mercator - Zone 10 (N) # coordinate system favorite. The # character appended to the name indicates this choices will override metrics and will not keep metrics from the old coordinate system. Manifold appends the # character so the favorites list automatically shows a change from the default keep metrics setting, without any need for us to rename the favorite or otherwise take manual action to indicate the favorite will override metrics.
Since new users might not be aware of the Manifold convention to append a # character to indicate a favorite coordinate system that overrides metrics, if we prefer we can edit the name of the coordinate system in the Favorites dialog to make it self-documenting, for example, Universal Transverse Mercator - Zone 10 (N) override. That will still appear in the list with a # character appended, but the use of the word override will remind new users what the # means.
Synonyms - Cartographers favor the term projection while programmers seem to prefer coordinate system. This documentation uses the two terms interchangeably, with the term projection tending to be used more in GIS or display contexts and the term coordinate system tending to be used more when discussing programming, SQL or standards.
Assign Initial Coordinate System
Favorite Base Coordinate Systems
Example: Convert a 0 to 360 Degree Projection - We often encounter data, both images and drawings, using latitude and longitude degrees that appears to be in Latitude / Longitude projection but which has longitude values from 0 degrees to 360 degrees and latitude values from 0 degrees to 180 degrees, instead of the usual arrangement of -180 degrees to 180 degrees for longitude centered on the Prime Meridian, and -90 degrees to 90 degrees for latitude centered on the Equator. This example shows how to utilize such data by assigning the correct projection.
Example: Assign Initial Coordinate System - Use the Info pane to manually assign an initial coordinate system when importing from a format that does not specify the coordinate system.
Example: Change Projection of an Image - Use the Reproject Component command to change the projection of an image, raster data showing terrain elevations in a region of Florida, from Latitude / Longitude to Orthographic centered on Florida.
Example: Adding a Favorite Coordinate System - Step by step example showing how to add a frequently used coordinate system to the Favorites system.
Example: Detecting and Correcting a Wrong Projection - A lengthy example exploring projection dialogs and a classic projection problem. We save a drawing into projected shapefiles and then show on import how a projection can be quickly and easily checked and corrected if it is wrong.
Reprojection Creates a New Image - Why changing the projection of an image creates a new image.
