Navigating your maps

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In these exercises we'll learn how to move around your map, query your data, select objects, and make measurements

We'll use tools available from the Navigation Toolbar, displayed at the top of the screen

Image:GIS_gis_Navi_01.jpg



Download sample data

For these exercises we are going to download a sample dataset: 'Sample Farm IA'

For this purpose, you can follow the steps detailed in Download sample data, but selecting 'Sample Farm IA' as the initial dataset, which can be found under the 'Tutorials_en' folder:

GeoAgro Gis-Navigating-000.jpg




Exercise 01 - Moving around your map

We'll review different options to move around your map


Double clicking on a layer

By double clicking on a layer, you will: turn the layer on, make it active, and zoom to the layer extent

  1. In the sample project, double click on layer 'State' - it will zoom to the extent of the State of Iowa

    GeoAgro Gis-Navigating-001.jpg
  2. Now click on layer 'Counties' - It will zoom to the extent of Counties (which of course is the same as the State), and also turn the Counties layer on.

    GeoAgro Gis-Navigating-002.jpg
  3. Now click on layer 'Fields_NRCS' - It will zoom to the Fields digitized in our sample project.

    GeoAgro Gis-Navigating-003.jpg

Zooming and Pan

There are different options to zoom around your map in the Navigation Toolbar:

Use the Rectangle Zoom Tool Rectangle Zoom Tool to zoom in or out using a zoom window, draw a rectangle around the Field 'a' to get closer view of that layer.

Image:GIS_gis_Navi_03a_02.jpg  →  GeoAgro Gis-Navigating-004.jpg

Go to the Navigation Panel and click on the Show Full Map tool Show full map extension. Next, the maximum extent for the visible layers will be shown on the work window.

GeoAgro Gis-Navigating-005.jpg

Pan Tool Pan - By pressing and holding the left mouse button, you will be able to navigate the map.

GeoAgro Gis-Navigating-006.jpg


Coordinate locator

Image:GIS_gis_Navi_06_01.jpg

You can also search for coordinates by clicking on the GPS coordinate locator, using a GPS coordinate taken from the field, or Google Earth for instance.

After you enter the coordinates, the screen will zoom in to the entered coordinates.

For this example, try entering the following coordinates:

Lat: N 42 15' 38.23"

Lon: W 93 23' 32.8"

Click on the Coordinate locator, enter the coordinates and click on 'Accept'. Your screen should look like this.

GeoAgro Gis-Navigating-007.jpg


Using the Scale

Double click on the scale value and enter a desired scale -> 1:12000

GeoAgro Gis-Navigating-008.jpg


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Exercise 02 – Selecting and Querying Data

Selection Tools

Several GeoAgro GIS operations require that you first select the features that you will work on. For instance, before modifying, copying, or editing attribute data, you need to select 


There are several ways of selecting an object, as you can see when expanding the selection tool.

Selection Tool


To select a feature, the order is:

  • Make the layer where the feature is located active
  • Use one of the selection tools to select a feature

Make the layer 'Fields_NRCS' by clicking on it. This layer contains fields downloaded or imported from the USDA NRCS.

Use the Select Point Image:GIS_gis_Navi_01a_01.jpg option and then click on the Field in the upper left corner:

Selection by Point - Click on the image to see it full size


To select contiguous fields, go to the option Rectangle Image:GIS_gis_Navi_01c_01.jpg and draw a rectangle that intersects three fields in the figure below:

Selection by Rectangle - Click on the image to see it full size


To unselect both fields click on Remove Selection Image:GIS_gis_Navi_01g_01.jpg or click anywhere outside the fields


Another way to select/unselect a field is by holding the Control key pressed while you select.

For instance, try selecting the two fields in the figure using the Point Selection tool Image:GIS_gis_Navi_01a_01.jpg, while holding the control key pressed.

GeoAgro Gis-Navigating-009.jpg


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Data Querying Tools

Select features in the 'NRCS Fields' layer, and export to excel

Now you will select fields 'a' and 'b' with the Select by Rectangle tool Image:GIS_gis_Navi_01c_01.jpg. To do that, draw a rectangle that intersects the mentioned fields :

Selection by polygon - Click on the image to see it full size

Go to the Query tool, and select the option 'Quey data by selection'.
Image:GIS_gis_Navi_07d_2.3.15_01.jpg

The attribute table for the objects you have selected will open.

Query selected objects - Click on the image to see it full size

You will next export the table in Excel format (.xls).


Export

Click on Export and save the table as fields_adc.xls. Then click OK.

Export data to Excel - Click on the image to see it full size

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Exercise 03 – Measuring

Measuring Tools

Double click on the layer called 'Tracts' under the 'Map Layout' group.

Then, go to the Navigation toolbar and expand the arrow in Measuring Tools Image:GIS_gis_Navi_04a_01.jpg and click on Length option Measuring Tool: Length.

Click on the upper left corner of the field 'a' and then double click on the upper right corner of it. You will automatically see the segment defined with the measured distance.

Length units Image:GIS_gis_Navi_04d_01.jpg can be selected right there. By default, GeoAgro GIS shows length in feets.

Measured distance in feets


You will now calculate the area of the same field expressed in acres.

In order to do that, go back to the navigation panel and expand the arrow in Measuring Tools Image:GIS_gis_Navi_04a_01.jpg and click on Surface option Image:GIS_gis_Navi_04a_01.jpg.

By clicking on each vertex of field 'a', and double-clicking on the last vertex that closes the plot, the surface of the polygon that has been created will be shown in acres.

The area units Image:GIS_gis_Navi_04c_01.jpg can also be selected right there.

Measuring area in acres

Measured area in acres

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