ArcGIS is a powerful desktop mapping application which can be used to view data in Shapefile, Personal Geodatabase and File Geodatabase formats.
For a short video showing how to view Geology Data in ArcGIS, click on the image below:
1. Accessing ArcGIS
ArcGIS, produced by ESRI, is available to UK academic institutions which are licensed under the CHEST/ESRI Agreement. Further details can be found at EDUSERV CHEST's web pages:
http://www.eduserv.org.uk/lns/agreements/esri. Not all institutions hold licenses under this agreement, in which case ArcGIS may not be available.
Instructions for starting ArcGIS will vary depending on how it is installed at your institution so you will need to find out how to run it locally. In Windows, a program can usually be run by either double clicking on an icon on the desktop, or by locating the program under the Windows Start menu. The ArcGIS program group may be at the following location: Start -> Programs -> ArcGIS
The ArcGIS program suite consists of a number of sub-programs; this document covers ArcMap and ArcCatalog only.
2. Preview and Prepare Data in ArcCatalog
When you download the shapefile data from Geology Digimap you will see that there are four component files to each layer and up to eleven layers per tile. These files need to be managed carefully as if the components are separated or renamed different things then the shapefile will not work. ArcCatalog provides an environment in which you can manage these files more easily, treating he component files as a single entity.
We strongly recommend that if you use ArcCatalog to move or rename shapefiles. You can also use ArcCatalog to establish a spatial reference for the data. This is stored in a separate .prj file not provided in the download. This is not necessary for the shapefile to display properly though it will help if you want to use the geology data with other different kinds of data.
ArcCatalog can be run from the ArcGIS programs group, usually: Start -> Programs -> ArcGIS -> ArcCatalog
After the ArcCatalog splash screen, the main ArcCatalog Interface will appear. Essentially you navigate to the location of your GIS data using the left panel and use the tabbed panels at right to find or change information about the dataset.
The first step in using ArcCatalog is to establish a link to your data held as Shapefiles. To do this click on the connect to folder icon
highlighted in the image above. A dialogue showing the windows directory tree will appear which you should use to navigate to the folder containing your data, select the folder and then click
OK, adding an entry to the
Catalog Tree. To see the full contents of this now connected folder, simply click the + node to expand the tree. Doing so should give you something like this:
You can at this point assign a spatial reference to the data. To do this, right click on a shapefile and select Properties, which will bring up the Shapefile Properties form. Go to the XY Coordinate System tab and click on the Select... button to select a predefined coordinate system.
Navigate through the folders:
Projected Coordinate Systems > National Grids > Europe > British National Grid.prj
Select this file and click Add. Finally click Apply and then OK to return to ArcCatalog; this step should be repeated for each of your Shapefile datasets.
Move on to the next section to see how to open up the shapefiles in ArcMap, this part of ArcGIS can be accessed directly from ArcCatalog by clicking on the ArcMap Icon:
3. Viewing data in ArcMap
ArcMap sits at the heart of ArcGIS and is used for all map-based tasks including cartography, spatial analysis and editing.
After the splash screen, the main ArcMap interface will appear.
The ArcMap interface consists of a table of contents on the left and a large panel to the right known as the data frame. Above these are a selection of drop-down menus and buttons which allow access to the various functions of ArcGIS. To add data to the data frame, click on the
Add Data
button located on the standard toolbar which will allow you to navigate to your data.
If you didn't use ArcCatalog before you opened up ArcMap then you will need to connect to your data folder to make finding your data more easily. Click on the connect to folder icon
and then navigate to the folder that contains your data. Highlight your folder and then click
OK, you will now be able to navigate directly to this folder every time you wan to add data.
Add in the shapefiles you have downloaded, you can use Ctrl or Shift keys to select multiple files at once:
To turn a layer on or off, simply click the tick box beside each layer. The properties of an ArcMap layer are accessed through the Layer Properties form. To access this form, double click on a layer item in the table of contents, or select a layer, and then right-click, and from the context menu choose, Properties.
4. Applying the BGS legend Colours
Although there are many properties associated with a layer we are perhaps most interested in setting how our data is drawn in ArcMap. To do this, click on the Symbology tab in the Layer Properties.
The symbology options available will vary depending on whether the layer is a point, line or polygon. You can manually edit the symbology but there are AVL files provided in your download that let you apply the official BGS Colour Scheme.
On the Layer Properties form, under the Symbology tab, click the Import button to bring up the Import Symbology form.
Set the radio button to Import symbology definition from an ArcView 3 legend file (*.avl): and then click the open file button to navigate to the AVL file; there is one for each shapefile in the data downloaded from Geology Digimap. Ensure that the lower left radio button panel is set to Complete symbology definition and then click OK.
At the Import Symbology Matching Dialog ensure that the Value Field drop-down for LEX_ROCK is also set to LEX_ROCK, and then click OK, returning you to the main Layer Properties form with the symbology applied. Note that for linear feature layers the Value Field should be Features not LEX_ROCK.
Finally click, Apply to return to ArcMap; repeat this process for the other layers to finish your geology map.
A full explanation of ArcMap's visualisation, Analysis and Editing functionality is beyond the scope of this document. However more detailed tutorials and information may be provided by your own institution. Every installation of ArcGIS comes with a number of ESRI digital books in PDF format which provide comprehensive coverage of ArcCatalog and ArcMap. To gain access to these you should contact the person who setup ArcGIS at your institution. Another alternative is the
ESRI virtual campus which provides a number of tutorials on ArcGIS.
