Merge pull request #517 from MerginMaps/iss_509-measurement-tools

add measurement tools

Author: tomasMizera

src/.vuepress/sidebar/en.js

@@ -96,6 +96,7 @@ module.exports = {
                 '/field/gps_accuracy/',
                 '/field/tracking/',
                 '/field/autosync/',
+                '/field/measure/',
                 '/field/layers/',
                 '/field/mobile-features/',
                 '/field/reuse-last-values/',

src/field/measure/index.md

@@ -0,0 +1,37 @@
+# Measurement Tools
+[[toc]]
+
+## Measure length and area in Mergin Maps mobile app
+In the <MobileAppNameShort />, it is possible to measure length and area on a map window. Measurement tools use the same units as are used by the QGIS project.
+
+To open the measurement tools, tap the **More** button in the bottom navigation panel and use the **Measure** option.
+   ![Mergin Maps mobile app Measurement tools](./mobile-measure.jpg "Mergin Maps mobile app Measurement tools")
+
+Use the **Add Point** button to add points along the line or area you want to measure
+- The *length* between added points is displayed in the **Measure** panel.
+- The current length is displayed near the crosshairs as you move them.
+- Use the **Undo** button to remove the last point.
+- To get the area, add the points along the shape. When you move the crosshairs close to the first point, you will see the **Close shape** option.
+
+When finished with the measurements, tap the **Done** for length measurement or **Close shape** for area measurement. The values of *perimeter* and *area* will be displayed in the **Measure** panel.
+
+![Mergin Maps mobile app measuring length and area](./mobile-measure-length-area.jpg "Mergin Maps mobile app measuring length and area")
+
+Tap **Repeat** to start a new measurement.
+
+Measured values are not saved.
+
+## Changing measurement units in QGIS
+Units that are used when measuring in the <MobileAppNameShort /> are defined (and can be changed) in the project in QGIS:
+
+1. Open your <MainPlatformName /> project in QGIS
+2. Navigate to the **General** tab in the **Project Properties**
+3. In the **Measurements** section, change the *Units for distance measurement* and *Units for area measurement* to the units you want to use when measuring length and area in the <MobileAppNameShort />
+4. Save and synchronise your project
+
+For example, here we switched to length units to feet and area units to acres.
+
+![QGIS length and area units setup](./qgis-project-properties-set-units.jpg "QGIS length and area units setup")
+
+Now, the <MobileAppNameShort /> displays the length/the perimeter in feet and the area in acres.
+![Mergin Maps mobile app measuring length and area in feet and acres](./mobile-measure-length-area-ft-ac.jpg "Mergin Maps mobile app measuring length and area in feet and acres")

src/field/measure/mobile-measure-length-area-ft-ac.jpg

@@ -124,7 +124,7 @@ More details can be found in [Layers in Mergin Maps Mobile App](../layers/).
 ![Mergin Maps mobile app Layers](./mobile-app-layers.jpg "Mergin Maps mobile app Layers")
 
 
-### More options: Zoom to project, Map themes, Position tracking, Local changes, Settings
+### More options: Zoom to project, Map themes, Position tracking, Measure, Local changes, Settings
 The **More** button opens a list of additional options
 
 ![Mergin Maps mobile app More button](./mobile-app-more-options.jpg "Mergin Maps mobile app More button")
@@ -133,6 +133,7 @@ The **More** button opens a list of additional options
 - [**Zoom to project**](../../gis/features/#project-extent): zoom to the extent of all visible layers within the project. The project extent can be set in [QGIS in Project Properties](../../gis/features/#project-extent).
 - [**Map themes**](../../gis/setup_themes/): a list of map themes set up in a <MainPlatformName /> project in QGIS
 - [**Position tracking**](../tracking/): to start tracking of your tracks during the field survey
+- [**Measure**](../measure/): measure length or area on the map
 - **Local changes**: the overview of your local changes to be synchronised
    ![Mergin maps mobile app Local changes](./mobile-app-local-changes.jpg "Mergin maps mobile app Local changes")
 - **Settings**: [GPS settings](#gps-settings), [streaming mode and recording settings](#streaming-mode-and-recording-settings), and general references to information about the <MobileAppNameShort />, changelog, help, privacy policy, terms of service and [diagnostic log](../../misc/troubleshoot/#diagnostic-log-on-mergin-maps-mobile-app)

src/field/measure/mobile-measure-length-area-ft-ac.xcf

@@ -1,4 +1,5 @@
 # Position Tracking
+[[toc]]
 
 Position tracking is useful when you want to record your tracks during the field survey. This can help you know the extent of areas you have already surveyed in addition to the surveyed features.
 

src/field/measure/mobile-measure-length-area.jpg

@@ -28,7 +28,7 @@ Various online and offline maps can be used as background layers for navigation
 ![QGIS Layer Capabilities](./qgis_project_properties.jpg "QGIS Layer Capabilities")
 
 ### Project extent
-In <MobileAppName />, there is an option to [zoom to the project extent](../field/mobile-app-ui/#more-options-zoom-to-project-map-themes-position-tracking-local-changes-settings). 
+In <MobileAppName />, there is an option to [zoom to the project extent](../field/mobile-app-ui/#more-options-zoom-to-project-map-themes-position-tracking-measure-local-changes-settings). 
 
 If the project extent is not set, <MobileAppName /> zooms to all visible layers. This is not particularly convenient when you have a layer with a large/global extent (e.g. Open Street Map). Instead, you may want to set the project extent to the area of your interest.
 

src/field/measure/mobile-measure-length-area.xcf

@@ -87,6 +87,7 @@ The ecosystem consist of various components:
 - [GPS Accuracy](./field/gps_accuracy/)
 - [Position Tracking](./field/tracking/)
 - [Synchronisation in <MobileAppName />](./field/autosync/)
+- [Measurement Tools](./field/measure/)
 - [Layers in <MobileAppName />](./field/layers/)
 - [How to Add, Edit, Delete Features](./field/mobile-features/)
 - [How to Reuse Last Entered Values](./field/reuse-last-values/)