# [Proj] Hooijberg's algorithm needed

Mikael Rittri Mikael.Rittri at carmenta.com
Sun Dec 30 05:23:04 EST 2012

```In Snyder's book, "Map Projections: A Working Manual", the symbol k stands for the local scale factor, and you can find formulas for k for an ellipsoid-based LCC projection at the top of page 108.

http://pubs.er.usgs.gov/publication/pp1395

It may be possible to compute k with Proj.4, but I don't know how to do that.

Regards,

Mikael Rittri
Carmenta
Sweden
http://www.carmenta.com

28 dec 2012 kl. 20:44 skrev "Achim Hasenmueller" <achim.hasenmueller at gmail.com<mailto:achim.hasenmueller at gmail.com>>:

Hi,

I'm interested in finding the relationship between scale factors of LCC maps
(aviation) that are designed so they can be put next to each other and therefore
have a different scale factor each.

The maps cover parts of Europe with standard parallels at 40°N and 52°N. The
scale factor differs slightly and I am interested in a formula to calculate it.
I have found this in a forum message from 2007:

"Find a chart that gives the true scale at 54ºN and divide that into 500,000.
This is the scale factor. For 51N the scale factor is 500/515=0.9709, = 1/1.03
Running Hooijberg's algorith for LCC, 2 parallels, the scale factor at
54N=0.97005."

Unfortunately a search for Hooijberg's algorithm was not successful. Any
pointers appreciated!

Thanks!
Achim
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