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written by Nigel James
 
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MAPINFO How to...  
No. 10: Manual geocoding  
(References to tables, folders etc., are not applicable outside the Map Room, so if you are located elsewhere, you should substitute your own)  
   

This explains how to use MapInfo to manually geocode point data. This is only required if you do not know the coordinate system for the map (such as a raster map). For information on normal geocoding, see MapInfo How to No. 6 Geocoding your data. For information on using raster images, see MapInfo How to No. 8: Using raster (scanned) maps and photos. MapInfo How to No.1 should be used for step-by-step instructions on creating maps and layouts.

 
   
 
1. Start MapInfo.  
 
2. Open the map table which you are going to use. If this is a raster map, it must have been registered with a suitable coordinate system (See MapInfo How to no 8 for more info).  
 
3. Open your data table. If you do not already have a data table in MapInfo format, see the MapInfo How to No 5 (Lat/Lon coordinates) or MapInfo How to No 6 (Ordnance Survey NG) for information.  
   
4. Click the title bar of your data table, then open the Table menu and click Table maintenance. Click Table structure and then click the Table is mappable checkbox. (If you cannot do this, it is because you are trying to change your original data table. You must always save a copy of the table and work with that copy - MapInfo takes care to stop you trashing your original data!)  
   
5. Click the Projection button which appears and set the projection to match your raster map. If you have not already selected a projection for your map (see MapInfo How to no. 8: Using raster (scanned) maps and images) then it will be in default lat/lon projection.  
   
6. Tile your data table window and map window by opening the Window menu and clicking Tile windows.  
   
7. This example assumes you have a table of placenames which correspond to places on your map. It could also be a table of street names and a street map, for example.  
   
8. Click the titlebar of the map window to make it active, then open the layer control.  
   
9. In the layer control, click the Add button and add your data table as a layer to the map. Make the data layer editable by clicking the Editable checkbox. Click OK to close the layer control.  
   
10. Click the map window titlebar to make it active, then click the symbol style button in the drawing toolbar. Choose a symbol.  
   
11. Click the box to the left of the first record in your data table. The box will turn black to show the record is selected.  
   
12. Click the symbol button in the drawing toolbox, then click once on the map where the corresponding place is. This will place a symbol which is linked to the current record.  
   
13. You have now geocoded your first place! Save the data table (File/Save table).  
   
14. Now select the another record in your data table and repeat the steps. (If you wisht o use diferent symbols, change the symbol style before clicking on the map to place the symbol).  
   
15. When you have geocoded all the places, you will have a mappable table of places.  
   
16. Your new table can if you wish be then be used to create thematic maps, using pie charts for example. Each pie will be located over the corresponding point symbol.  
   
17. If a record has been geocoded wrongly, make the data table layer editable, select the record (which will also select the corresponding symbol) and drag the symbol to its correct position. Remember to uncheck the editable checkbox and save the table again.  
   
Extracting coordinates form your map and saving them in the table  

When you have geocoded your data, you may wish to add the coordinates to your table, so they can be seen when the table is opened in a browser window. This can be done for any coordinate system and the results will be in the units selected for your table (e.g: Lon/Lat, eastings and northings in metres for OS National Grid etc). To do this, see MapInfo Howto No. 15: Extracting coordinates and saving them in a table.

 
   
This is a brief and specific guide to this topic, for more general information, see: MapInfo l - an easy guide for new users  
Nigel James
Bodleian Library 2001
 
Bodleian Library Map Room