Accessed in the **Component** pane by clicking
the coordinate system picker button for the component.

Modern formats designed to store spatial data will automatically specify
the coordinate system to be used for the data they provide. Data
from such sources will import seamlessly into Manifold with the initial
coordinate system automatically assigned. In the **Component** pane the coordinate
system for the component will appear in **black**
text, indicating it has been assigned and the component is ready to go.

If the coordinate system is shown in **red**
color, we *must* click the coordinate
system picker button and choose **Assign
Initial Coordinate System**.

Manifold shows the coordinate system in **black**
color, as in the Latitude / Longitude coordinate system seen above at
left, when the component has been created with coordinate system information
or if it has been imported from a format that specifies the coordinate
system to use. When a component has been created *without*
specifying the coordinate system or it has been imported from a format
that does *not* specify projection
information, Manifold will show the default **Pseudo
Mercator** coordinate system as a placeholder in **red**
color.

When the coordinate system appears in **red**
text that warns us the component was imported from a source that failed
to specify the initial coordinate system. That happens when
acquiring data from older formats or from sources, such as CAD or photography
formats, not designed to store spatial data.

Manifold will assign a placeholder coordinate system, the default **Pseudo-Mercator** system, for the
component to use until we manually can assign the correct initial coordinate
system.

The **red** text
tells us we *must* assign the initial
coordinate system manually by using the **Assign
Initial Coordinate System** command. Until we use
that command to assign the initial coordinate system the read-out for
that component will use **red**
text. Once we assign the initial coordinate system the read-out
will switch to **black** text.

Assigning an initial coordinate system
is easy: Click the coordinate system picker button in the the **Component** pane and under **Assign Initial Coordinate System**
unfolds a menu that allows one of three choices:

**Edit Coordinate System**- This launches the**Coordinate System**dialog to enable choosing any one of thousands of coordinate systems.

**Choose one of the listed favorites**- By default, Manifold always provides Latitude / Longitude and Pseudo Mercator as default favorites. If other coordinate systems have been added to our favorites, those also will appear in the list.

**Edit Favorites**- Launch the Favorites dialog to enable us to add a new favorite if we like. This is a convenience that allows us to right away add another coordinate system that we know we will want as a favorite.

See the **Coordinate
System** topic for details on using that dialog.

When we must use this command, we only use it **once
**after initial import or linking of a component. After it
is used once the command will no longer appear. If we make
an error applying this command, we can repair the error by using the **Repair
Initial Coordinate System **command that thereafter will be available.

For a step-by-step illustrated example using the Assign Initial Coordinate
System command, see the **Example:
Assign Initial Coordinate System** topic.

**Important:** If
we import or link data only from modern formats designed for spatial data
storage we might never see this command or need to use it. It appears
as an option *only* for those components
brought into a project that Manifold knows were imported or linked from
formats that failed to specify the initial coordinate system.

**No changes to data** - Assigning
an initial coordinate system does **not**
change the coordinate numbers embedded in a drawing's geometry and it
does **not** change pixels in images.
It only specifies the correct coordinate system property to
be associated with that drawing or image so the data they contain makes
sense as intended.

**Difficulties** - There are two
difficulties using Assign Initial Coordinate System:

**Knowing what to assign** - People
publish projected data all the time in spatially brain-dead formats which
do **not** convey projection information
and then they fail to tell users what projection they used.

The **red** text
along with a choice limited to Assign Initial Coordinate System warns
us that the source of the data failed to specify the coordinate system,,
but if we do not know from other means (such as reading a description
of the data on a web site) what coordinate system should be used we cannot
manually assign it using the command.

We might get lucky, try **Latitude /
Longitude**, and discover the data looks OK against a "known
good" layer like Bing. But that's fake luck in many circumstances
because we will not know if a default datum choice like WGS84 is the right
one, and not NAD27 or some other datum that also produce a visually close
alignment.

The best approach is to sharpen our detective skills, to carefully search the website from which we downloaded the data and to carefully review any accompanying metadata files to see if we can find an authoritative statement of what coordinate system was used.

**Keeping the careless at bay**
- People who do not read instructions will often misuse Assign Initial
Coordinate System by thinking it is used to *change*
a coordinate system that has already has been correctly assigned. They
want to change projection from what they think is Pseudo Mercator to some
local projection, they click on the coordinate system picker button and
the only choice they see enabled is **Assign
Initial Coordinate System**, with the **Change Coordinate System**
choice disabled. So they choose Assign Initial Coordinate System
and proceed to choose the projection they want.

The result is total chaos because first, the initial coordinate system has now been wrongly assigned, and second, the red text that was used to warn that the coordinate system was probably wrong will now be replaced with black text and the coordinate system that they specified.

Instead of changing the projection they take a perfectly good image
or drawing that was ready to be made useful through intelligent use of
Assign Initial Coordinate System, and they assign the **wrong**
coordinate system to that data.

Prevent this problem by ensuring all people who you allow to work with
your data know that when they see **red** text
and the sole choice of Assign Initial Coordinate System they should **not** do anything further before
checking with you. Forbid them from using **Assign
Initial Coordinate System** until you review their work and have
verified they can be trusted not to misuse the command.

**Synonyms** - The terms **projection**
and **coordinate
system **are used as interchangeable synonyms in Manifold. 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.

**Trust Manifold** - If the coordinate
system readout for a component appears in **red**
text in the **Component**
pane and Manifold allows only the choice of **Assign
Initial Coordinate System** from the coordinate system picker button,
we should not argue with the system, no matter how sure we are that the
data that was imported or linked came with a specification of initial
coordinate system. Believe the initial coordinate system was
not specified and use the command to specify it manually.

Data that is thought to contain coordinate system info frequently does
not. People forget to include necessary files, files get damaged
when edited by the wrong software (see the commentary on killing GeoTIFFs
in the **TIF**
topic) and sometimes people publish data assuming everybody on Earth will
by default use exactly the same coordinate system they do, so they do
not include all info required for those who do not base all thought upon
Universal Transverse Mercator Zone 42 (S).

Repair 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 **Component** 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 **Change Coordinate System**
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.

**Re-Projection
Creates a New Image** - Why changing the projection of an image
creates a new image.