Landscapes are composed of ecosystems, so I think it is better to delineate the latter. You need to decide on your scale first using topographical maps. Then use a methodological approach to spatially delimitate ecological systems and boundaries within the landscape. For example, you can place transect plots and measure species abundance and analyse/plot the results using cluster analysis or canonical ordination, etc.

See:

Wetlands Ecology and Management, pp 1–14

Delineating landscape-scale processes of hydrology and plant dispersal for species-rich fen conservation: the Operational Landscape Unit approach

And:

Delineating the Ecosystems Containing Protected Areas for Monitoring and Management, BioScience (2011) 61 (5): 363–373.

DOI: https://doi.org/10.1525/bio.2011.61.5.5

There are over 155 National Forests in USA, with varying geology, soils, climate, hydrology, trees, plants, ecosystems.  Forest plans are developed or revised about every decade or two, and are public documents that you may find with some hunting at usfs.gov.  With some searching and time, I think you might find some examples of forest management considerations with some embeddedor adjacent land uses.  These documents tend to be fairly comprehensive and long, with much detail.  Generally forests use GIS to store layers of geology, soils, topography, land ownership and use, streams, watersheds, forest and vegetation types, ecological or habitat units, recreation sites, roads, age and density of forest stands, wildwrness, etc. These layers help the team of technical specialists as they consider management options that would lead to desired conditions.  The forest planning and environmental impact assessments functions under specific code of federal regulations.

As 'Landscape planning' is the aim, your expert planning advise (or statutory plan?) will be bound by property and land use zoning law. Both property and zoning boundaries are a given and can be overlaid in GIS.

Examples of zoning and property categories can be found my Bolivia tropical forest and my Majella NP (bear) article. 

I wonder as a land use zoning practitioner what the competent authority, or most probably authorities for the 'planning' is/are in this case.  

There are many types of landscape analysis: based on landscape ecology, based on visual landscape analysis, based on integrated landscape analysis, etc.

At present, I am working on a study (planning project) of landscape impact of a large industrial zone on a landscape listed in World Heritage Sites (UNESCO). In my project, I combine overlay analysis, visual analysis, cluster analysis... but finally I delineate the landscape structure based on my expert knowledge, and integrating criteria.

I think that a integrated landscape analysis is much more than a simple overlay analysis because of this landscape analysis involves a series of subjective judgments in relation to study area, the impact of human activity, and the environmental legislation at a regional level (in accordance with the laws of the State, European Directives, Unesco rules).

In your case, I suppose it is a landscape ecology analysis or an ecogeographical analysis, but I am not sure. What is the aim of your planning project?

Can't you use discriminant analysis?

Sorry, it is not my area of experience to contribute information