DIVA Support

Hi. I'm Samantha Green from Western Australia and I'm trying to downscale some of the DIVA  input values for my Honours project. Is it possibe to put smaller scaled population data into DIVA? And is it possible to use modified line segements with smaller scaled geomorphic data in DIVA? 

Also where can I download the Advanced User Mode from?

Any help you can give me would be greatly appreciated. Thank you

Sam

Hi Samantha,

Nice to hear that you're using DIVA. To be able to understand the DIVA data, I suggest you study the database description:

\DIVA\Tool\Docs\Vafeidis, A.T. et al, 2005 DIVA dbase documentation.pdf

provided with the tool.

A. Population data comes into DIVA in the following parameters/files:

1. During segmentation population density classes were used as one of the deciding factors for segmentation.

2. cls_iv.his (initialised CLS variables):

    - pop (Coastal Population)

    - popdens (Coastal Population Density)

3. Scenario data by country in the selected SRES_XYZ.SCN folder:

    - popgrowth (Annual growth rate of population)

So if you want to change population data, these are the files you need to consider. The most straightforward data to change would be better coastal population data by coast line segment (CLS), followed by better country population growth rates. Another data area that can be improved are the average slope and AREA_X values. These were made using a fairly coarse elevation grid. In many areas there are now better elevation data from the space shuttle mission. As all results are closely linked to the slope at sea level, this is an important improvement opportunity.

B. Segmentation

Changing segmentation is a difficult and ambitious process. Many data have been derived for those segments (see the database paper). Once you change the segmentation all that needs to be redone. If you need to go in that direction, I think you will need some help to make sure that a new running model comes out of it. I suggest you start with updating the population data (and perhaps other CLS parameters as well) using the existing segmentation. Once that works, you can start by inserting CLS (essentially duplicating a CLS record, and renumbering all necessary IDs). Of course you need to change parameters like the length of the segment and other parameters as well. It must be done for all CLS input files: cls_iv.his and cls_p.his (for all cases). Also don't forget the SRES_XYZ.SCN\landuse.his files for all the SRES scenario's!!

If you keep splitting for each segment you want to add, you will be OK as far as the model is concerned. Getting all the CLS parameters correct values is some work too.

C. Advanced user mode

It is not that exciting, it only allows you look at results for coastline segments (normally hidden). This is essential for your work. To be able to look at CLS results, you have to edit the userlevel entry in the \diva\tool\diva.ini file as follows:

[Settings]
UserLevel=1

Kind regards,

Poul Grashoff

Hi Poul.

I attempted to add another coastline segment into DIVA and was hoping you could tell me if I've done it correctly.

I added a new location in the cls_p.his and changed the latitude, longitude, length and cpc and kept all other parameters the same as the original segment which was split in 2.

I then added a new location to cls_iv.his and kept all values the same except for pop and popdense.

I changed these for all cases and then added another location to the landuse.his in each scenario and for each timestep.

When I look at the cls input parameters un DIVA it has inserted a new row with the data values that I changed. However, the correct location of the new segment does not appear in the map layout and the last row (12147 New Zealand) has been deleted. Do you know why this is? Am I following the right steps for inserting a coastal segment? Thankyou.

Sam