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Appropriate and Inappropriate Use of GAP Data

All information is created with a specific end use or uses in mind. This is especially true for GIS data, which is expensive to produce and must be directed to meet the immediate program needs. For GAP, minimum standards were set (see Standards Chapter in the GAP Handbook) to meet program objectives. These standards include: scale or resolution, accuracy, and format. The standards are constantly evolving, and therefore projects begun previous to the date of the current standards may not meet those standards.

Recognizing, however, that GAP would be the first, and for many years likely the only, source of statewide biological GIS maps, the data were created with the expectation that they would be used for other applications. Therefore, we list below both appropriate and inappropriate uses. This list is in no way exhaustive but should serve as a guide to assess whether a proposed use can or cannot be supported by GAP data. For most uses, it is unlikely that GAP will provide the only data needed, and for uses with a regulatory outcome, field surveys should verify the result. In the end, it will be the responsibility of each data user to determine if GAP data can answer the question being asked, and if they are the best tool to answer that question.

Scale

First we must address the issue of appropriate scale to which these data may be applied. The data were produced with an intended application at the ecoregion level, that is, geographic areas from several hundred thousand to millions of hectares in size. The data provide a coarse-filter approach to analysis, meaning that not every occurrence of every plant community or animal habitat is mapped, only larger, more generalized distributions. The data are also based on the USGS 1:100,000 scale of mapping in both detail and precision. When determining whether to apply GAP data to a particular use, there are two primary questions: do you want to use the data as a map for the particular geographic area, or do you wish to use the data to provide context for a particular area? The distinction can be made with the following example: You could use GAP land cover to determine the approximate amount of oak woodland occurring in a county, or you could map oak woodland with aerial photography to determine the exact amount. You then could use GAP data to determine the approximate percentage of all oak woodland in the region or state that occurs in the county, and thus gain a sense of how important the county’s distribution is to maintaining that plant community.

Appropriate Uses

The above example illustrates two appropriate uses of the data; as a coarse map for a large area such as a county, and to provide context for finer-level maps. Following is a general list of applications:

• Statewide biodiversity planning
• Regional (Councils of Government or ecoregional) planning
• Regional habitat conservation planning
• County comprehensive planning
• Large-area resource management planning
• Coarse-filter evaluation of potential impacts or benefits of major projects or plan initiatives on biodiversity, such as utility or transportation corridors, wilderness proposals, regional open space and recreation proposals, etc.
• Determining relative amounts of management responsibility for specific biological resources among land stewards to facilitate cooperative management and planning
• Basic research on regional distributions of plants and animals and to help target both specific species and geographic areas for needed research
• Environmental impact assessment (EIS) for large projects or military activities
• Estimation of potential economic impacts from loss of biological resource based activities
• Education at all levels and for both students and citizens

Inappropriate Uses

It is far easier to identify appropriate uses than inappropriate ones, however, there is a "fuzzy line" that is eventually crossed when the differences in resolution of the data, size of geographic area being analyzed, and precision of the answer required for the question are no longer compatible. Examples include:

• Use of the data as a "content" map for small areas (less than thousands of hectares), typically requiring mapping resolution at 1:24,000 scale and using aerial photographs or ground surveys.
• Combining GAP data with other data finer than 1:100,000 scale to produce new hybrid maps or answer queries resulting in precise measurements.
• Generating specific areal measurements from the data finer than the nearest thousand hectares (minimum mapping unit size and accuracy affect this precision).
• Establishing exact boundaries for regulation or acquisition.
• Establishing definite occurrence or nonoccurrence of any feature for an exact geographic area (for land cover, the percent accuracy will provide a measure of probability).
• Determining abundance, health, or condition of any feature.
• Establishing a measure of accuracy of any other data by comparison with GAP data.
• Altering the data in any way and redistributing them as a GAP data product.
• Using the data without acquiring and reviewing the metadata and this report.