I am now working on a system to perform routing on a network of shipping lanes. See this dataset that I have as the base: http://geocommons.com/maps/109850 I have postgres and pgrouting up and running and I was able to run basic queries on the above dataset after importing it to postgres/postgis. However I have encountered some problems for which I seek advice from you.
A lot of lines have a duplicate, so say line A goes from source id 1 to source id 2 and line B goes from source id 2 to source id 1 and they overlap completely. This can be experienced a lot of times, and frankly, I would be happy to get rid of them so that finally I could have a network with only one polyline per direction.
I discovered that the distance value attributes of the referenced dataset are false. I noticed this when I checked the dataset with Global Mapper by using the Info tool. In the window that pops up, you can see the geometry textbox with bounds and length data. For a line I inspected that displayed a length value of 5300 some kilometres while the max value in the length column of the dataset was 110. I seek for a way to acquire those polyline length values, and assign them to a new attribute column. I have already found posts about how to do this in qgis and arcgis, but neither of them provided the results I wanted to get. The route dataset is in WGS84, latlon
I hope the lines above make sense, and I appreciate any help! Thanks in advance!