Spatial Data

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“Spatial Data Interview Questions and Answers will guide us that spatial data is a framework of spatial data, meta-data, users and tools that are interactively connected in order to use spatial data in an efficient and flexible way. Spatial Data is the technology, policies, standards, human resources, and related activities necessary to acquire, process, distribute, use, maintain, and preserve spatial data, learn more about Spatial Data with Spatial Data Interview Questions with Answers guide”



29 Spatial Data Questions And Answers

7⟩ Resolution may best be defined as

1. the smallest feature that can be mapped or measured

2. the smallest unit or measurement into which data can be disaggregated

3. the overall quality of a data set

4. the size of the smallest recording unit

5. the accuracy and precision of the data

The size of the smallest recording unit

the smallest feature that can be mapped or measured

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11⟩ What is Edge matching?

Edge matching is simply the procedure to adjust the position of features that extend across typical map sheet boundaries. Theoretically data from adjacent map sheets should meet precisely at map edges. However, in practice this rarely occurs. Misalignment of features can be caused by several factors including digitizing error, paper shrinkage of source maps, and errors in the original mapping. Edge matching always requires some interactive editing. Accordingly, GIS software differs considerably in the degree of automation provided.

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14⟩ What is Conflation?

Conflation is formally defined as the procedure of reconciling the positions of corresponding features in different data layers. More commonly this is referred to as sliver removal. Often two layers that contain the same feature, e.g. soils and forest stands both with a specific lake, do not have exactly the same boundaries for that feature, e.g. the lake. This may be caused by a lack of coordination or data prioritization during digitizing or by a number of different manipulation and analysis techniques. When the two layers are combined, e.g. normally in polygon overlay, they will not match precisely and small sliver polygons will be created. Conflation is concerned with the process for removing these slivers and reconciling the common boundary.

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19⟩ What is coordinate thinning?

Coordinate thinning involves the weeding or reduction of coordinate pairs, e.g. X and Y, from arcs. This function is often required when data has been captured with too many vertices for the linear features. This can result in redundant data and large data volumes. The weeding of coordinates is required to reduce this redundancy.

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20⟩ What is geometric transformations?

Geometric transformations function is concerned with the registering of a data layer to a common coordinate scheme. This usually involves registering selected data layers to a standard data layer already registered. The term rubber sheeting is often used to describe this function. Rubber sheeting involves stretching one data layer to meet another based on predefined control points of known locations. Two other functions may be categorized under geometric transformations. These involve warping a data layer stored in one data model, either raster or vector, to another data layer stored in the opposite data model. For example, often classified satellite imagery may require warping to fit an existing forest inventory layer, or a poor quality vector layer may require warping to match a more accurate raster layer.

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