Drawing Polygons

Drawing a Polygon Feature

Touch GIS offers 3 methods for drawing a polygon feature. Begin by tapping the blue '+' button in bottom right corner of the map. Here you'll see all available feature classes. Select the polygon type feature class you want to add to your project.

Basic Draw is the default drawing mode in Touch GIS. Tap 'Mode' at the bottom center of the map to access the Free Draw or Record With GPS methods.

Basic Draw Method:

1. Start by panning and zooming the map so your desired staring location is in the crosshairs.

2. Tap 'Add Point' to add the first point of your polygon.

3. Pan and zoom to position the next desired point in the crosshairs.

4. Tap 'Add Point' to add the second point in your polygon.

5. Repeat this step until you've added all the points necessary to draw your polyong feature. Note: A polygon feature must 'close', so the first and last point draw will automatically connect to make a solid shape.

6. Tap 'Save' to add the polygon feature to your layers and add attributes.

Tip: You can undo and redo point placements in your polygon if needed using the buttons to the left and right of the 'Add Point' button.

Free Draw Method: This method allows you to use your finger or a stylus (preferably an Apple pencil) to draw a polygon. This method is useful for quick data collection where accuracy is less important.

Record With GPS Method: Make sure your device is located where you want to start recording before you begin.

1. Tap 'Start Recording'

2. Begin moving and proceed move along the perimeter of your polygon.

3. Tap 'Save' when you're done recording to add the polygon feature to your layers and add attributes.

Editing a Polygon Feature

To edit a polygon feature simply select it on the map and tap 'edit' at the bottom center of the map view. In edit mode, you can select which node you'd like to move. Simply select a node then pan and zoom the map to reposition it. You can use the arrow buttons to cycle through nodes on complex features. In addition to the main nodes there are also midpoints. These are displayed inbetween two nodes and appear smaller than the main nodes. Tapping a midpoint will create a new node that you can then place independently. Use this method to add more detail to your feature.

Note: If you have imported a polygon with inner polygons (cut outs within a larger body) you will not be able to edit their geometry. You will be able to manage their attributes.

Deleting a Polygon Feature

You can delete a feature by selecting it and tapping 'Delete' at the bottom center of the map. You can also delete features from the Layers dialog.