ArcGis Tutorial.docx

**[ArcGIS Tutorial]** **1. Settings** **1.1 Launching ArcMap**  Go to the start button \> All programs \> ArcGIS and launch ArcMap  Check start using ArcMap using a "A new empty map" **1.2 Hide/Show tool box**  Click on the toolbox tool to show or hide the Arc toolbox **1.3 General Setting...

**[ArcGIS Tutorial]** **1. Settings** **1.1 Launching ArcMap**  Go to the start button \> All programs \> ArcGIS and launch ArcMap  Check start using ArcMap using a "A new empty map" **1.2 Hide/Show tool box**  Click on the toolbox tool to show or hide the Arc toolbox **1.3 General Settings**  Right click anywhere in the toolbox and click on Environments  Click on general settings Specify the directory for the current workspace and scratch workspace (*you can use* *the same folder*) and leave the rest as default **1.4 Setting the document properties**  In order to ensure that one can safely copy and open an ArcMap project on another computer or even from another location on the same computer, there is the need for the document property to be set.  Click on file on the menu bar \> document properties  Click on data Source Options  Check store relative path names to data sources **1.5 Customising menus**  Right click anywhere on the menu bar and click on Tools to activate it  Can you see the tool bar now? **2. Adding Data to the data frame** **2.1 Adding points, lines, polygons and X-Y data**  Click on the add data tool Browse to your training folder and add District !38. Close the geographic coordinate systems warning box if it pops up. You should have a map similar to the one below in your display window (the colour could be different since it is chosen at random) Now add the District\_caps old and the Region shapefile by holding down the control key and selecting them together. Note that when you add shapefiles, points will automatically (by default) be on top ofa line and a polygon. You can however manually change the order by dragging the Shapefile and placing it where it is needed.  In order to see two polygons superimposed on each other, there is the need to change the transparency of the one on top or make it hollow so the one below can be visible. Click on the symbol below the District\_138 in the data frame to change the properties. Change the District\_138 fill colour to yellow, outline colour to red and the outline width to 2 if they are different.  The result should look like the one below - Right click on the District\_138 and click on Open attribute table to view the information on the shapefile The attribute table should be similar to the one below with additional fields. Data in the attribute table can be sorted. Calculations can also be performed. You will see that later Right click on the District\_138 \> properties or double click on the District\_138 Click on the Symbology tab Click on categories \> Unique values  For value field select DISTRICT  Click on "Add All values" and uncheck "all other values"  Click on Apply and see the resulting map (*like the one below*) depending on the colour Ramp chosen.  Use the zoom-in tool to zoom in to the Upper East Region of Ghana by clicking on the tool and drawing a rectangle around the upper right corner of the District\_138 map  Put the Regions layer on top of the District\_138 layer  Now make the Regions hollow but increase the outline width to 1.5 and change the colour to red like the one shown below Right click on the Region layer and click on zoom to layer to see the whole layer.  Sort the data in the attribute table of the District\_138 and select all the Upper East districts  Right click \> zoom to the selected features  Now you can see the District and Regional boundaries overlap which shouldn't be the Case **2.2 Spatial Analyses**  You will create a regional shapefile out of the district shapefile using the dissolve tool so that the boundaries do not overlap *If you did not know where to get the dissolve tool you could search for it in the toolbox*  Click on the search tab \> type dissolve \> click on search Once you are sure of the tool you will like to use, click on the locate button so you can easily locate it the next time one has to use it else you can double click on it to use the tool straightaway.  Once you click on the locate, it will take you to the specific toolbox where it could be found as shown below for the dissolve tool.  Select the District\_138 as the input feature and specify the output feature class (*ensure that you name it Region\_138*) Select **Region** as the Dissolve field so that districts in the same region could have their extents/boundaries put together to form their regional boundary. Leave the rest as default.  The status bar should inform you to know whether you were successful with the operation or not.  The Region\_138 shapefile is created and added to the data frame Now make the Region\_138 layer hollow and zoom in to the Upper East Region. What do you see now with regards to the boundary issues? Add the old Region layer \> make it hollow and change the outline so you can distinguish between the old regional boundary and the new one. Is there any difference?  Zoom in to the Region\_138 and turn all other layers off  Double click on Region\_138 to change its properties  Click on the label tab \> Choose region for the label field (*you can explore the text* *symbol and other options like placement of labels*) \> Apply \> Ok You can also use an expression for the label field especially of you want to use two or more fields for the labelling. Can you try that? Now right click on the Region\_138 and click on label features The label should appear as below. Check the label for the Greater Accra Region. You will realise that there is a mistake which needs to be corrected. Open the attribute table for the Region\_138 layer. You will notice the mistake in the label for Greater Accra. This has to be corrected  Right click on the menu bar and activate the editor tools Click on the Editor tool \> Start editing Select the correct folder where the data base/layer to be edited (Region\_138) is Stored/saved \> Ok.  Open the attribute table for Region\_138 and correct the text  Click on the editor \> save edits \> stop editing  Zoom in to the Region\_138 with the labels added  Click on the select tool to select the Upper East region **SELECTION BY ATTRIBUTE** In the main menu Click on Selection \> Select by Attributes  Select Region\_138 as the layer  For Method select "Create a new selection"  Double click on the Region \> Click on get unique values \> click on the equal sign \> click on Upper East as shown above in the diagram. When you are done, you can verify if the expression is correct by clicking on the verify  After issuing the query, you will notice that the Upper East Region has been selected as shown below  In the table of content Right click on the source layer for the Upper East Region ie (Region\_138) \> Data \>Export Data  Specify the output shapefile \> click on Ok When the pop up window requests whether you will like to add the exported data to the map as a layer select yes. The Upper East boundary is added as shown below Turn all layers apart from the Upper East Region boundary off  Zoom in to the Upper East (UE) Region ***Clipping***  Go to Analysis Tools \> double click on Clip  Specify District\_138 as the input features and Upper East boundary as the Clip feature. This is to enable you get all the districts within the UE region as UE\_District\_138 The resulting map should be the same as the one below but the colour could be Different. **Change the symbology to the one below and label the districts** Refer to pages 11-12. Add the roads layer and clip it for only the UE region to get UE\_Road After clipping. DELETING OF FIELD (COLUMNS)  Open the attribute table for UE\_District\_138  Right click on any field that is not needed in the attribute table and delete. With this method you can delete more than one field at a time  This could also be done easily with the Data Management Tools and multiple fields could be deleted at a go  Confirm the deletion by clicking on the Yes button when the pop up below shows up  Go to Data Management in the tools box \> Fields \> double click on Delete field  Specify UE\_District\_138 as the input table and select the fields that need to deleted \>Ok  After deletion, you should have an attribute table such as the one below  You can also add fields to the attribute data. Here you will create a field for the computation of the Area of the district for population density computations  Click on the options button in the attribute information \> Add field  There is the need to specify the type (Float, Integer or Text). Float is used when you expect the field to contain some fractions else use Integer. In instances where the field will just be strings (e.g. names or labels) then use text.  Type the name of the field ( in this instance we want to compute the areas of the districts in square kilometres) as **Area\_sqkm** **3. Geometry and Field Calculations** Geometry and fields could be computed when one opens the attribute table but fields could also be calculated using the Data Management Tools **3.1 Geometry Calculation**  This calculation has to be done by opening the attribute table  Right click on the field where for example the Area\_sqkm is to be computed  Click on calculate Geometry  You will be prompted that you want to do the computation outside the edit session as computations can be done within or without an edit session Click on yes when you are outside the edit session. When you are in the edit session this window will not pop up. For the property to be computed select Area \> Use the appropriate coordinate system, For calculating the Area in sq km in this instance you can use the coordinate system of the data frame or the data source since it is the same. (*you have to pay particular attention here*)  For units select Square Kilometres (sq km)  Click on OK  The result should be similar to the one below ***You can also format the numbers. For example reduce the number of decimal places to*** ***zero (0). To do this,***  Right click on the Area\_sqkm field \> click on properties  The field property window is opened as shown below  Click on Numeric  Change the number of decimal places to 0  The results is shown below **Adding XY -Data** To add XY-data, the data has to be well prepared in excel or any other spread sheet and saved as \*.xls, \*.xlsx or any other recognised text format (e.g. \*.csv). X and Y represent the longitude and latitude respectively or the Easting and Northing respectively. *Before the data is added ensure that the excel file or text file is closed. This helps a lot but* *can be done without*  Go to the Tools menu \> Add XY Data *For this exercise, you will plot the LPG Stations in Ghana using XY data* *In your normal computer window, browse to the National LPG and open the excel sheet to* *ensure that it is well prepared and you understand the coordinate system used for the XY* *data. Close the workbook once you have familiarise yourself with the data.* ***Quick questions:*** *From the excel data, how many LPG Stations in Ghana do you have their coordinates?*  Click on the browser tool and browse to the location of your exercise folder and select All\_regions  Click on Add.  For the X-Field select X\_Z30N\_m and for the Y-Field Y\_Z30N\_m. What does the Z30N\_m mean?  Click on the edit button to specify the coordinate system of the data  Click on select on the Spatial reference Properties window.  Double click on the Projected Coordinate Systems  Click on the WGS 1984 \> WGS 1984 UTM Zone 30N.prj coordinate system and Add The reference system is shown below. Compare yours with the one below to make sure you have selected the correct one.  Once you are satisfied, click on Apply \> OK  Your final window should now look the one below and Click on OK.  The XY data now has to be exported to shapefile. You have done this in an earlier exercise so try it yourself.