[idvusers] Vector drawing problems

I have a problem drawing vector fields when using my own formula and custom 
lat/lon projections in IDV 2.7u2. It seems that the eastward component is 
scaled incorrectly in my own projection, i.e. the eastward component is scaled 
down such that my vectors always either point north- or southward.

To isolate the problem I defined a formula to make vectors with equal size u 
and v components (1,1):

makeVector( newName(a/a, "u") , newName(a/a, "v") )

I plotted this using 3 lat/lon projections (see attached image, zoomed in on 
Gulf of Aden):
- predefined 'world'
- predefined 'africa'
- custom, my own region defined using projection manager

In all 3 cases the vectors point in a different direction (they tend to rotate 
to the North). Only in the 'world' projection, the vectors seem correct. What's 

(I have posted this question in another thread some weeks ago but haven't 
received an answer, apologize if I am being too impatient).

Reinoud Bokhorst
Advisor Oceanography & ICT

Tel:    +31 (0)527-242 299
Fax:    +31 (0)527-242 016
Web:    www.bmtargoss.com

BMT ARGOSS P.O. Box 61, 8325 ZH Vollenhove
Voorsterweg 28, 8316 PT Marknesse
The Netherlands

PNG image