"Accessibility" is arguably the single most important ecoregional factor driving land use change and development in general. It is surprising, therefore, that initial work on multi-scale analysis by the research team that developed the Conversion of Land Use and its Effects (CLUE) model (Veldkamp and Fresco, 1996) that inspired this Project, did not include "accessibility" or even mention it as a potential driver for land use change. We are in agreement with Geertman and van Eck (1995) who said, "The concept of accessibility is used as a means in rural development policy, an indicator of rural deprivation, and as a variable in location analysis".

Deichmann (1997), in his report on software development for assessing accessibility, describes four "accessibility indicators" that the development community is using for assessing "service provision", for example, in the health sector. Although this use is undeniably important, the Project wished to explore other uses for which the methodology would be valuable. To mention a few examples:

• How are concepts and measures of accessibility affected by levels of analysis?
• At community landscape levels, are there practical thresholds to potential productivity of individual "fields" solely as a result of their geographical location; and can they be mapped?
• How can accessibility concepts and algorithms be applied to watercourse conservation and management?

The analytical model is a cost-distance, spatial, cell-based approach that defines the ease each cell (i.e., location) can be accessed from other locations, in this case villages, by generating something called a friction or cost surface.

Figure 4 shows accessibility maps (in terms of travel time) that are a variation on the theme "potential accessibility indicator". Combining data for roads before October 1998 and 3730 villages (called aldeas in Honduras) created the map in Figure 1a. Villages represent a set of sources and targets. From this basic network, least-cost transport routes were calculated taking into consideration geographical factors impeding movement, such as slope and land cover. It is important to keep in mind that this map represents only one of several possible stakeholder perspectives of the concept of accessibility. Our goal was to create a tool flexible enough to incorporate a wide range of perspectives and indicators.

In October 1998, Hurricane Mitch devastated Honduras. Virtually overnight, the accessibility map shown in Figure 4a was made obsolete. An updated map (Figure 1b) was developed within hours of the hurricane and made available to and used by relief agencies to help target disaster relief. This use of the accessibility analysis "wizard" and ecoregional database on CD-ROM may have been serendipitous, but it is a powerful example supporting our initial hypothesis-that narrowly conceived perceptions of development opportunities arbitrarily limit the range of valuable "outside" information.

Generating alternative ecoregions - the econoshed.

Modern agricultural location theory stems from the seminal contributions of David Ricardo and Johan Heinrich von Thunen nearly 200 years ago. Today, most of the spatial variation in agricultural land use depends on only two factors:

1. Differences in physical features: for example, soil fertility, climate, and topography; and
2. (2) Differences in relative location: for example, transportation costs to markets. Mulligan (1997) points out that, "Even after the suggestion of McCarty and Lindberg (1966) some 30 years ago, few serious attempts have been made to synthesize these two complementary approaches to agricultural location theory".

We propose that the concept of accessibility, based on the spatial structure of markets, transport networks, and topography, could provide a common framework in which to attempt such a synthesis. Surfaces of accessibility define "catchment" areas for each market. These catchments ("econosheds") are a new set of user-defined areal units ideal for describing ecoregions, and as such are a powerful extension to the Von Thunen model. Figure 5 illustrates one possible set of these new ecoregions that are neither political units nor watersheds.