Diversity mapping on Google Earth

Google Earth maps can be generated from any file with lat/long fields. This includes the Distribution summary table (DST) and the diversity file generated as a by-product of that.

You can plot normal map points from the DST table or, if grid cells are used as part of the geo-resolution, you can plot the cells as polygons related to grid cell size. In both cases, you can use colours/symbols/size with the plotted points or cells to reflect content - and when mapping from the DST, this may reflect diversity.

The following examples are generated from the confier database (data provided by A. Farjon, RBG Kew). You can use your own data to replace the examples provided here.

Check the map colours and symbols files and add a map style scheme

Map style schemes speed up adding mapping colours and symbols to data files. You can edit colours and symbol values manually or using FoxPro commands - but using map style schemes speed things up greatly.

Schemes allow you to classify data according to field values or ranges - and for each value or range, to add a map style. For example, using a map style scheme, you could colour points related to selected altitude ranges, size points related to tree DBH or use different symbols for different taxa.

Select Maps > Colours. If the file is empty, a selection of sample colours with Hexadecimal codes (as used by Google Earth) will be added (see below). Close the file having checked it.

Select Maps > Symbols. If the file is empty, a selection of sample symbols (on Oxford DPS server) for Google Earth will be added (see below). GE symbols are image files that must reside on a server accessible on the web. Close this file having checked it.

Select Maps > Map style schemes.
Add a new record with map scheme name 'Species diversity'.
Click the toolbar to open this scheme and edit as follows:

Notes: Some fields (e.g. Legend, Size here have been left blank). Use F9 in the COL and SYM fields to lookup values from the above mentioned tables. The scheme code (in this example 2) matches the entry Species diversity. The number may be different in your case. Colours are represented by Hexadecimal codes preceded by 2 digits to reprsent opacity. FF is fully opaque. You can also use the single letter colour codes currently assigned within BRAHMS.

Close this file.

You can experiment with further map schemes.

Extract botanical records

While not strictly necessary, this extract step will speed up the processing.

Extract all Botanical records from the country 'New Caledonia'.
Close the extract file. The extract will be used to restrict DST processing in the next stage.

Generate the distribution summary data

Select DistSum > Add/edit grid cell definitions and add an entry to represent 1/4 degree cells as shown below:

Note the CELLSIZE is set to the decimal value 0.25.

Select DistSum > View/refresh DST for current database. Select the Re-calc toolbar and choose the options as show below

Note the following:

The data source is set to Vouchered botanical records.
A data restriction is applied to speed things up: Extracted botanical records.
The taxa resolution is Species + ssp/var/f.
The Geo resolution is Grid cell and the cell size is set to 1/4 degree squares.
The option Create diversity sum table is selected.

Select Calculate to produce the table.

Note: you may be asked to generate quick codes for taxa. If so, use the default code generation settings as prompted.

Close the DST table and select DistSum > Summarize DSTdiversity indicators per area. The sum table was created as the Create diversity sum table was selected above.

Select Tools > Map tools > Apply a style scheme. Choose the 'Species diversity' scheme and tick the col/sym options

Run this option using Select. This will colour and symbol your records based on the values in the SPTOTAL field (shown as 'speciestotal' in the data grid.

Now select the toolbar to open the map form. Select Google Earth as the software option. Also select Draw polygons for cell boundaries. In this example, the polygons are not filled (try filled and not filled) and the line weight is set to value 2.

Finally, select Map all.

Cells plotted as 1/4 degree polygons. Use Ctrl+click to show text. The text includes the taxa that occur in the cell. Map data provided by A. Farjon, RBG Kew

The same data but with filled polygons. Map data provided by A. Farjon, RBG Kew

Points rather than polygons plotted. Map data provided by A. Farjon, RBG Kew

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