Does anybody openly publish conversion factors (e.g. for miles in different modes of transport, food, etc) into global hectares for ecological footprint?
Global Footprint Network, so far as I can tell, only make this data available through licensing their software.
The ecological footprint method does not directly convert consumed resources into global hectares, at least not via a single conversion factor. Instead first the amount of required land/sea area in physical hectares is calculated by dividing the amount of resources by the yield of the specific land/sea area where those resources were harvested. The physical hectares for each land type are then converted into global hectares by multiplying with both 'yield factors' (YF) and 'equivalence factors' (EQF).
As a formula:
EcoFootprint = (amount resource used / national average resource yield) * YF * EQF
The yield factor for a land type is the ratio between the national average yield and the world average yield on that type of land. In other words it accounts for land type productivity differences between countries. Obviously yield factors vary per country and per year.
The equivalence factor for a land type indicates how much higher/lower the productivity of that land type is compared to the world average productivity. In other words, it allows aggregating different land types into one common global hectare measure. Equivalence factors vary per year but by definition not per location.
The Global Footprint Network (GFN) regularly publishes yield and equivalence factors in reports and data packages, but you have to pay a fee to obtain those unless you qualify for non-commercial educational usage (this page on the GFN website mentions the exact requirements). Alternatively you can find other reports on the Internet that mention factors for particular years. For example page 15 of this report shows the equivalence factors for 2005, and page 22 of this report mentions those for 2006
2005 2006
------------------------------------
Primary cropland 2.644 2.39
Forest 1.333 1.24
Grazing land 0.497 0.51
Fishing grounds 0.397 0.41
Built-up land 2.644 2.39
Carbon 1.333
The second report also mentions the yield factors for a few countries in 2006
Cropland Forest Grazing Fishing
Algeria 0.6 0.4 0.7 0.9
Germany 2.1 4.1 2.2 3.0
Hungary 1.4 2.6 1.9 0.0
Japan 1.5 1.4 2.2 0.8
Jordan 1.0 1.5 0.4 0.7
New Zealand 1.9 2.0 2.5 1.0
Zambia 0.5 0.2 1.5 0.0
Chances are this data is not very useful to you, but many online reports do demonstrate how ecological footprint calculations are done. If it's only for one country you may be able to follow the reports as an example and gather the required data yourself using public information?
If you want to calculate the EF for a product or organisation you also need to determine the amount of consumed primary inputs. This can be rather challenging as there is no single accepted procedure here. For example, the person doing the calculation defines the exact boundaries of what is and isn't included.
I've read somewhere that there is (some?) product information available in the GFN National Footprint Accounts reports, but I can't verify this myself at the moment. Alternatively there are both open-source and proprietary life-cycle analysis (LCA) databases that provide information about the resources used to produce certain products or services (see also the info wiki of the life-cycle-analysis tag). Whether or not data is publicly available depends on the product or service you are looking for. Note that older LCA data or data from other countries can be used, but may be less accurate for the product or process you are interested in.
