202 changes: 98 additions & 104 deletions source/docs/user_manual/introduction/general_tools.rst
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Expand Up @@ -1080,40 +1080,36 @@ General information

QGIS provides four means of measuring geometries:

* the interactive measurement tools |measure|,
* measuring in the |calculateField| :sup:`Field Calculator`,
* derived measures in the :ref:`identify` tool,
* and a vector analysis tool: :menuselection:`Vector --> Geometry Tools -->
* interactive measurement tools |measure|
* measuring in the |calculateField| :sup:`Field Calculator`
* derived measurements in the :ref:`identify` tool
* the vector analysis tool: :menuselection:`Vector --> Geometry Tools -->
Export/Add Geometry Columns`

Measuring works within projected coordinate systems (e.g., UTM) and unprojected
data. The first three measuring tools behave equally to global project settings:

* If :guilabel:`"on the fly" CRS transformation` (see :ref:`otf_transformation`)
is enabled, the default measurement metric is
- different from most other GIS - ellipsoidal, using the ellipsoid defined in
* Unlike most other GIS, the default measurement metric is
ellipsoidal, using the ellipsoid defined in
:menuselection:`Project --> Properties... --> General`. This is true both
when geographic and projected coordinate systems are defined for the project.
* If you want to calculate the projected / planimetric area or distance using cartesian
maths, the measurement ellipsoid has to be set to "None / Planimetric"
* If you want to calculate the projected/planimetric area or distance using cartesian
maths, the measurement ellipsoid has to be set to "None/Planimetric"
(:menuselection:`Project --> Properties... --> CRS`). However,
with a geographic (= unprojected) CRS defined for the data and project, area and
with a geographic (ie unprojected) CRS defined for the data and project, area and
distance measurement will be ellipsoidal.
* If :guilabel:`"on the fly" CRS transformation` is disabled, the measurement
metric is planimetric when the project coordinate system is projected and
ellipsoidal when the project coordinate system is unprojected / geographic.

However, neither the identify tool nor the field calculator will transform your
data to the project CRS before measuring. If you want to achieve this, you have
to use the vector analysis tool: :menuselection:`Vector --> Geometry Tools -->
Export/Add Geometry Columns`. Here, measurement is by default planimetric except
if you choose the ellipsoidal measure.
Add Geometry Attributes...`. Here, measurement is planimetric, unless
you choose the ellipsoidal measurement.

Measure length, areas and angles interactive
............................................
Measure length, areas and angles interactively
..............................................

Click the |measure| icon in the Attribute toolbar to begin measurements.
The downward arrow near the icon helps you switch to the convenient tool to measure
The down arrow near the icon switches between
|measure| length, |measureArea| area or |measureAngle| angle.
The default unit used in the dialog is the one set in :menuselection:`Project -->
Properties... --> General` menu.
Expand All @@ -1124,7 +1120,7 @@ Properties... --> General` menu.
at the bottom of the widget opens the :menuselection:`Settings -->
Options --> Map Tools` menu, where you can select the rubberband color, the
precision of the measurements and the unit behavior. You can also choose your
preferred measurement or angle units but keep in mind that those values are
preferred measurement or angle units, but keep in mind that those values are
overridden in the current project by the selection made in the
:menuselection:`Project --> Properties... --> General` menu, and by the
selection made in the measurement widget.
Expand All @@ -1140,21 +1136,20 @@ tools, each mouse click (within the tolerance setting) will snap to that layer.
single: Measure; Areas
single: Measure; Angles

By default, |measure| :sup:`Measure Line`: QGIS measures real distances
By default, |measure| :sup:`Measure Line` measures real distances
between given points according to a defined ellipsoid.
The tool then allows you to click points on the map. Each segment length,
as well as the total, shows up in the measure window.
To stop measuring, click your right mouse button.
To stop measuring, click the right mouse button.

Note that you can use the drop-down list near the total to interactively change
the measurement units while working with the measure tool ('Meters', 'Kilometers',
'Feet', 'Yards', 'Miles', 'Nautical miles', 'Centimeters', 'Millimeters', 'Degrees',
'Map units').
This unit is kept for the widget until a new project is created or another project
Note that you can use the drop-down list near the total to change
the measurement units interactively while working with the measure tool ('Meters', 'Kilometers', 'Feet', 'Yards',
'Miles', 'Nautical miles', 'Centimeters', 'Millimeters', 'Degrees', 'Map units').
This unit is retained for the widget until a new project is created or another project
is opened.

The :guilabel:`Info` section in the dialog explains how calculations are made
according to CRS settings available.
according to the CRS settings available.

.. %FixMe: currently, validating the Settings --> Options dialog revert any change
made on units in the measurement dialog (see https://issues.qgis.org/issues/15436
Expand Down Expand Up @@ -1183,7 +1178,7 @@ different area units ('Square meters', 'Square kilometers', 'Square feet', 'Squa

|measureAngle| :sup:`Measure Angle`: You can also measure angles. The
cursor becomes cross-shaped. Click to draw the first segment of the angle you
wish to measure, then move the cursor to draw the desired angle. The measure
wish to measure, then move the cursor to draw the desired angle. The measurement
is displayed in a pop-up dialog.

.. _figure_measure_angle:
Expand Down Expand Up @@ -1213,47 +1208,47 @@ Interacting with features
Selecting features
------------------

QGIS provides several tools to select features in the map canvas. Selection
tools are available in :menuselection:`View --> Select` menu or in the
QGIS provides several tools to select features on the map canvas. Selection
tools are available in the :menuselection:`View --> Select` menu or in the
:guilabel:`Attributes toolbar`.

.. note::

Selection tools work with the currently active layer.

Selecting manually in the map canvas
Selecting manually on the map canvas
....................................

To select one or several features with the mouse, you can use one of the following
To select one or more features with the mouse, you can use one of the following
tools:

* |selectRectangle| :sup:`Select Features by area or single click`
* |selectPolygon| :sup:`Select Features by Polygon`
* |selectFreehand| :sup:`Select Features by Freehand`
* |selectRadius| :sup:`Select Features by Radius`

.. note:: Except the |selectPolygon| :sup:`Select Features by Polygon` tool, these
manual selection tools allow you to select feature(s) in the map canvas with a
.. note:: Other than |selectPolygon| :sup:`Select Features by Polygon`, these
manual selection tools allow you to select feature(s) on the map canvas with a
single click.

.. note:: With the |selectPolygon| :sup:`Select Features by Polygon` tool, it is
possible to use an existing polygon to select overlapping features.
.. note:: Use the |selectPolygon| :sup:`Select Features by Polygon` tool
to use an existing polygon to select overlapping features.
Right-click in the polygon and choose it from the context menu that shows a
list of all the polygons that contain the clicked point.
All the overlapping features from the active layer are selected.

While using the |selectRectangle| :guilabel:`Select Feature(s)` tool,
holding :kbd:`Shift` or :kbd:`Ctrl` toggles whether feature is selected
holding :kbd:`Shift` or :kbd:`Ctrl` toggles whether a feature is selected
(ie either adds to the current selection or remove from it).

For the other tools, different behaviors can be performed holding:
For the other tools, different behaviors can be performed by holding down:

* :kbd:`Shift`: add features to the current selection
* :kbd:`Ctrl`: substract features from the current selection
* :kbd:`Ctrl+Shift`: intersect with current selection, ie only keep
overlapping features from the current selection
* :kbd:`Alt`: select features that are totally within the selection shape.
Combined to :kbd:`Shift` or :kbd:`Ctrl` keys, you can add or substract
Combined with :kbd:`Shift` or :kbd:`Ctrl` keys, you can add or substract
features to/from the current selection.

.. _automatic_selection:
Expand All @@ -1262,45 +1257,45 @@ Automatic selection
...................

The other selection tools, also available from the :ref:`Attribute table
<sec_attribute_table>`, perform a selection based on feature's attribute
<sec_attribute_table>`, perform a selection based on a feature's attribute
or its selection state (note that attribute table and map canvas show the
same information, so if you select one feature in attribute table, it will
be selected in map canvas also):
same information, so if you select one feature in the attribute table, it will
be selected on the map canvas too):

* |expressionSelect| :sup:`Select By Expression...` allows user to select
features using expression dialog.
* |expressionSelect| :sup:`Select By Expression...` select
features using expression dialog
* |formSelect| :sup:`Select Features By Value...` or press :kbd:`F3`
* |deselectAll| :sup:`Deselect Features from All Layers` or press
:kbd:`Ctrl+Shift+A` to deselect all selected features in all layers.
:kbd:`Ctrl+Shift+A` to deselect all selected features in all layers
* |selectAll| :sup:`Select All Features` or press :kbd:`Ctrl+A` to select all
features in the current layer.
features in the current layer
* |invertSelection| :sup:`Invert Feature Selection` to invert the selection in
the current layer.
the current layer


For example, if you want to find regions that are boroughs from
:file:`regions.shp` of the QGIS sample data, you can use the |expressionSelect|
:sup:`Select features using an Expression` icon. Then, you expand the
:sup:`Select features using an Expression` icon. Then, expand the
:guilabel:`Fields and Values` group and choose the field that you want to query.
Double-click the field 'TYPE_2' and also click :guilabel:`All Unique` in the
panel that shows up. From the list, choose and double-click 'Borough'. In the
:guilabel:`Expression` field, then you'd write the following query:
:guilabel:`Expression` field, write the following query:

::

"TYPE_2" = 'Borough'

From the expression builder dialog, you can also use the :menuselection:`Function
list --> Recent (Selection)` to make a selection that you used before. The
dialog remembers the last 20 used expressions. See :ref:`vector_expressions`
chapter for more information and some example.
From the expression builder dialog, you can also use :menuselection:`Function
list --> Recent (Selection)` to make a selection that you have used before. The
dialog remembers the last 20 expressions used. See :ref:`vector_expressions`
for more information and examples.


.. tip:: **Save your selection into a new file**

Users can save selected features into a **New Temporary Scratch Layer** or a
**New Vector Layer** using :menuselection:`Edit --> Copy Features` and
:menuselection:`Edit --> Paste Features as` in the wanted format.
:menuselection:`Edit --> Paste Features as` in the desired format.

.. index::
single: Selection tools; Select by value
Expand All @@ -1310,10 +1305,10 @@ chapter for more information and some example.
Select Features By Value
........................

This selection tool opens the layer's feature form allowing the user to choose,
for each field, which value to look for, if the search should be case sensitive,
and the operation that should be used. The tool has also the autocompleter function
that fills automatically the search box with the existing values.
This selection tool opens the layer's feature form allowing the user to choose
which value to look for for each field, whether the search should be case-sensitive,
and the operation that should be used. The tool has also autocompletes,
automatically filling the search box with existing values.

.. _figure_filter_form:

Expand All @@ -1322,7 +1317,7 @@ that fills automatically the search box with the existing values.

Filter/Select features using form dialog

Alongside each field, there is a drop-down list with the operation options to
Alongside each field, there is a drop-down list with options to
control the search behaviour:

============================================= ============ ============ ============
Expand Down Expand Up @@ -1350,23 +1345,23 @@ control the search behaviour:
For string comparisons, it is also possible to use the |checkbox|
:guilabel:`Case sensitive` option.

After setting all search options, you can use the :guilabel:`Select features`
button to select the matching features. The drop-down options are:
After setting all search options, click :guilabel:`Select features`
to select the matching features. The drop-down options are:

* :guilabel:`Select features`
* :guilabel:`Add to current selection`
* :guilabel:`Filter current selection`
* :guilabel:`Remove from current current selection`

You can also clean all search options using the :guilabel:`Reset form` button.
You can also clear all search options using the :guilabel:`Reset form` button.

Once the conditions are set, you can also either:

* :guilabel:`Zoom to features` in the map canvas without the need of a preselection;
* or :guilabel:`Flash features`, highlighting the concerned features. This is a
* :guilabel:`Zoom to features` on the map canvas without the need of a preselection
* :guilabel:`Flash features`, highlighting the matching features. This is a
handy way to identify a feature without selection or using the Identify tool.
Note that the flash does not alter the map canvas extent and would be visible only
if the feature resides in the current canvas.
if the feature is within the bounds of the current map canvas.

.. index::
single: Identify features
Expand All @@ -1378,49 +1373,49 @@ Identifying Features
The Identify tool allows you to interact with the map canvas and get information
on features in a pop-up window. To identify features, use:

* :menuselection:`View --> Identify Features` menu,
* or press :kbd:`Ctrl+Shift+I` (or |osx| :kbd:`Cmd+Shift+I`),
* or click the |identify| :sup:`Identify Features` icon on the Attributes toolbar.
* :menuselection:`View --> Identify Features`
* :kbd:`Ctrl+Shift+I` (or |osx| :kbd:`Cmd+Shift+I`),
* |identify| :sup:`Identify Features` icon on the Attributes toolbar

Using the Identify Features tool
................................

QGIS offers several ways to identify features with the |identify|
:sup:`Identify Features` tool:

* **left click** will identify features according to the
* **left click** identifies features according to the
:ref:`selection mode <identify_mode>` and the
:ref:`selection mask <identify_selection>` set in the
:guilabel:`Identify Results` panel
* **right click** with :guilabel:`Identify Feature(s)` as
:ref:`selection mode <identify_mode>` set in the :guilabel:`Identify Results`
panel will fetch all the snapped features from all the visible layers.
This will open a context menu, allowing the user to choose more precisely the
panel fetches all snapped features from all visible layers.
This opens a context menu, allowing the user to choose more precisely the
features to identify or the action to execute on them.
* **right click** with :guilabel:`Identify Features by Polygon` as
:ref:`selection mode <identify_mode>` in the :guilabel:`Identify Results`
panel will identify the features that overlap with the chosen existing
panel identifies the features that overlap with the chosen existing
polygon, according to the :ref:`selection mask <identify_selection>` set in
the :guilabel:`Identify Results` panel

.. tip:: **Filter the layers to query with the Identify Features tool**

Under :guilabel:`Layer Capabilities` in :menuselection:`Project --> Properties...
--> Data Sources` tab, uncheck the :guilabel:`Identifiable` column next to a
--> Data Sources`, uncheck the :guilabel:`Identifiable` column next to a
layer to avoid it
being queried when using the |identify| :sup:`Identify Features` tool in a mode
other than **Current Layer**. This is a handy way to return features from
only layers that are of interest for you.

If you click on feature(s), the :guilabel:`Identify Results` dialog will list
information about the clicked feature(s). The default view is a tree view where
information about the feature(s) clicked. The default view is a tree view in which
the first item is the name of the layer and its children are its identified feature(s).
Each feature is described by the name of a field along with its value.
This field is the one set in :menuselection:`Layer Properties --> Display`.
Then follows all the other information about the feature.
All the other information about the feature follows.

Feature informations
....................
Feature information
...................

The Identify Results dialog can be customized to display custom fields, but by
default it will display the following information:
Expand All @@ -1433,32 +1428,32 @@ default it will display the following information:
is added, namely ``View feature form`` for editing. You can define more actions
in the layer's properties dialog (see :ref:`actions_menu`).
* **Derived**: This information is calculated or derived from other information.
This includes:
It includes:

* general information about its geometry:
* general information about the feature's geometry:

* depending on the geometry type, the cartesian measurements of length,
perimeter or area in the layer's CRS units;
perimeter or area in the layer's CRS units
* depending on the geometry type and if an ellipsoid is set in the project
properties dialog for :guilabel:`Measurements`, the ellipsoidal values of
length, perimeter or area using the chosen units;
* the count of geometry parts in the feature and the number of the part you
clicked on;
* and the count of vertices in the feature.
length, perimeter or area using the specified units
* the count of geometry parts in the feature and the number of the part
clicked
* the count of vertices in the feature
* coordinate information, using the project properties :guilabel:`Coordinates
display` settings:

* the ``X`` and ``Y`` coordinate values of the clicked point;
* the number of the closest vertex to the clicked point;
* the ``X`` and ``Y`` (and ``Z``/``M`` if applicable) coordinate values of the
closest vertex;
* in case you click on a curved line using the info tool, QGIS will also
display the radius of that section in the panel result.
* ``X`` and ``Y`` coordinate values of the point clicked
* the number of the closest vertex to the point clicked
* ``X`` and ``Y`` coordinate values of the
closest vertex (and ``Z`/`M`` if applicable)
* if you click on a curved segment,
the radius of that section is also displayed.
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Suggested change
the radius of that section is also displayed.
and the click is in the middle of that element, its radius is also displayed.

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@havatv havatv Jan 24, 2019 •
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I just tested this in QGIS 3.4.4. You need to click closer to the second point that defines the circular string than to the ends in order for the radius to be displayed. So my suggestion is not entirely correct.

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"and the click is in the middle of that element". This condition does not apply. Radius seems to be always there as column. And only filled for vertices that are on a curved segment.

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I really should go and sleep. I don't know why I was trying with the vertex tool instead of the identify one. /me going away....

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That is what I indicated in my previous comment.
In my "Identify Results" window, I only see the "Closest vertex radius" line when my click is closest to the middle defining point of the circular string. I don't see a radius column, so I guess we are looking at different things.


* **Data attributes**: This is the list of attribute fields and values for the
feature that has been clicked.

.. note:: Links in feature's attributes are clickable from the :guilabel:`Identify
.. note:: Links in the feature's attributes are clickable from the :guilabel:`Identify
Results` panel and will open in your default web browser.

.. _figure_identify:
Expand All @@ -1476,15 +1471,15 @@ At the top of the window, you have a handful of tools:
* |formView| :sup:`Open Form` of the current feature
* |expandTree| :sup:`Expand tree`
* |collapseTree| :sup:`Collapse tree`
* |expandNewTree| :sup:`Expand New Results by Default` to define whether next
identified features information should be collapsed or expanded
* |expandNewTree| :sup:`Expand New Results by Default` to define whether the next
identified feature's information should be collapsed or expanded
* |deselectAll| :sup:`Clear Results`
* |editCopy| :sup:`Copy selected feature to clipboard`
* |filePrint| :sup:`Print selected HTML response`

.. _identify_selection:

* and selection mode to use to fetch features to identify. it can be:
* selection mode to use to fetch features to identify:

* |identifyByRectangle| :sup:`Identify Features by area or single click`
* |identifyByPolygon| :sup:`Identify Features by Polygon`
Expand All @@ -1498,25 +1493,24 @@ At the top of the window, you have a handful of tools:

.. _identify_mode:

At the bottom of the window, you have the :guilabel:`Mode` and :guilabel:`View`
At the bottom of the window are the :guilabel:`Mode` and :guilabel:`View`
comboboxes.
With the :guilabel:`Mode` combobox you can define from which layers features
should be identified:
:guilabel:`Mode` defines from which layers features should be identified:

* **Current layer**: only features from the selected layer are identified. The
layer may not be visible in the canvas.
* **Top down, stop at first**: for only features from the upper visible layer.
* **Top down**: for all features from the visible layers. The results are shown in
layer need not be visible in the canvas.
* **Top down, stop at first**: only features from the upper visible layer.
* **Top down**: all features from the visible layers. The results are shown in
the panel.
* and **Layer selection**: opens a context menu where the user selects the layer to
identify features from. Operates like a right-click. Only the chosen features
* **Layer selection**: opens a context menu where the user selects the layer to
identify features from, similar to a right-click. Only the chosen features
will be shown in the result panel.

The :guilabel:`View` can be set as **Tree**, **Table** or **Graph**.
'Table' and 'Graph' views can only be set for raster layers.

The identify tool allows you to |checkbox|:guilabel:`Auto open form`.
If checked, each time a single feature is identified QGIS will open a form
If checked, each time a single feature is identified, a form opens
showing its attributes. This is a handy way to quickly edit a feature's attributes.

Other functions can be found in the context menu of the identified item. For
Expand All @@ -1525,7 +1519,7 @@ example, from the context menu you can:
* View the feature form
* Zoom to feature
* Copy feature: Copy all feature geometry and attributes
* Toggle feature selection: Adds identified feature to selection
* Toggle feature selection: Add identified feature to selection
* Copy attribute value: Copy only the value of the attribute that you click on
* Copy feature attributes: Copy the attributes of the feature
* Clear result: Remove results in the window
Expand Down