Constructing an interpolated genetic map

It is often difficult to construct a good genetic map of a large number of SNPs. Typically this involves interpolation between a genetic map and the physical map of the SNPs. 
 
The Cartographer web site at 
 
https://apps.bioinfo.helsinki.fi/software/cartographer.aspx 
 
looks like it might ease this task. 
 
Here is a description of what Cartographer does from a recent paper: 
 
"Cartographer retrieves the physical location of the markers from the University of California Santa Cruz (UCSC) database and orders the markers based on the sequence information. The genetic location of each marker is defined using the published deCODE genetic map [51], which are also stored in the UCSC database. For markers that were not included in the deCODE genetic map, we used linear interpolation for obtaining estimates of the genetic locations of these markers by using the physical and the genetic locations of the immediately flanking deCODE markers. Also, if the physical location from the UCSC database and the genetic location from the deCODE genetic map for a given marker were in disagreement, we obtained an estimate of the genetic location via interpolation using the nearest flanking deCODE markers that are in agreement with the sequence information. For those markers that were not found in the UCSC database, we retrieved PCR primers from UniSTS and used these to map the marker using UCSC in-silico PCR, and performed the linear interpolation to obtain an estimate of the genetic location as described previously [14]." 
 
From: 
Combined Genome Scans for Body Stature in 6,602 European Twins: Evidence for Common Caucasian Loci Perola M, Sammalisto S, Hiekkalinna T, Martin NG, Visscher PM, et al. PLoS Genetics Vol. 3, No. 6, e97 doi:10.1371/journal.pgen.0030097 
 
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For an alternative approach to constructing interpolated genetic maps, see David Duffy's discussion.