To do the analysis described below using ArcGIS 9.3 you will need to create a "relate" between data in the quarter quad index file qq.shp and the quarter quad csv table qq_eos.csv downloadable from our website.
For selections to be enabled between tables in a relate, the tables must all have an ObjectID column. There is not an ObjectID column in qq_eos.csv, so it must be converted to a data format with an ObjectID column such as a geodatabase or a dBase dbf file. Below we convert it to a dBase dbf file.
Converting the CSV file to a DBF file
- In ArcCatalog navigate to the CSV file, qq_eos.csv.
- Right click on the CSV file and select "Export" and then "To dBase (single)".
- For "Output Location" enter the complete path to the folder where you want the DBF file to reside.
- "Output Table" should be qq_eos.dbf
- Under "Field Map" make sure the "area code" field is listed as "(Text)". If not, right click, select properties and change type to text.
Making and saving the relate
- In ArcGIS desktop "Data View", click on the "Source" tab at the bottom of the Table of Contents.
- Using the "Add Data" button on the button bar, bring qq.shp and qq_eos.dbf into ArcGIS .
- Right click on "qq" and select "Joins and Relates" and select "Relate".
- In the "Relates" dialog, for field 1 select "area_code", for 2 select "qq_eos", for 3 "id_code". Then for 4 give the relate the name "qq eos" and select "OK".
- Save your project and the relate will be saved for future work.
Using quarter quads to select rare element records
- Right click on the "qq" layer and open the attribute table. Do the same for qq_eos.
- Select one or more quarter quad records either from the table or on the map.
- At the bottom of the qq attribute table select "Options" and then select "Relate Tables" and select the relation you made above.
- The records in qq_eos for the selected quarter quads will now be selected.
- To only show these records, click "Selected" at the bottom of the qq_eos table.
Create a range map for a Bald Eagles
- From "qq_eos" options at bottom of the table choose "Select by Attributes..." to open the Select by Attributes dialog.
- For method select "Make a new selection".
- For field select "SCOMNAME".
- Click the equals ("=") button.
- Type Bald Eagle between single quotes ( 'Bald Eagle' ) or alternately select "Get unique values" and select Bald Eagle from the list.
- From the qq_eos table options select "Related tables" and choose the relate to the quarter quad index table. This will select the quarter quads that have bald eagles in them.
- To show just the quarter quads that have bald eagles go to the table of contents on the map, right click on qq, chose "Selection" and then "Create layer from selected features."
- If you want to rename the new layer to "Bald Eagles" right click on the layer name and select "Properties". From the "General" tab, under "Layer Name" type in the new name and click "O.K".