Reach Analysis¶

Reach analysis is available under Analysis > Reach for all-source calculations and Analysis > Interactive Reach for selected-source calculations.

Metric Reach¶

Path: Analysis > Reach > Metric Reach

Metric Reach computes the total length of segments reachable within a metric radius. A radius of 500 creates a Shapefile field named R500 and a CSV/TXT field named R_500.

Metric Reach parameters — Metric Reach parameter panel.¶

Metric Reach also generates mean metric distance, such as mMD500, because the same search process can compute both reachable length and average metric distance.

Directional Reach¶

Path: Analysis > Reach > Directional Reach

Directional Reach uses turn counts and an angle threshold. Directional Change = 2 and Angle Threshold = 20 creates a field such as R2d20a.

Directional Reach parameters — Directional Reach parameter panel.¶

For regular grids, an angle threshold around 5 to 10 degrees is often sufficient. For organic networks, 15 to 30 degrees may be more appropriate. A turn count of 2 is often useful for identifying the difference between main streets and ordinary streets.

Junction Reach¶

Path: Analysis > Reach > Junction Reach

Junction Reach limits the search by the number of junctions. Junctions = 5 and Degree Thresholds = 4 means that only 4-way intersections are counted as junctions, producing a field such as R5j4x.

Junction Reach parameters — Junction Reach parameter panel.¶

Combined Reach¶

Path: Analysis > Reach > Combined Reach

Combined Reach applies both a metric radius and a directional radius. For example, 500 m, 2 turns, and 20 degrees describes segments reachable within 500 meters and no more than two directional changes.

Combined Reach parameters — Combined Reach parameter panel.¶

Options¶

Reach options include junction counting and weighted calculations.

Weighted Reach parameters — Weighted Reach field selection.¶

Weighted calculations use selected numeric fields as the quantity being reached. For example, weighted reach by Shopcount estimates the amount of reachable shop-related activity rather than only reachable street length.

Interactive Reach¶

Interactive Reach computes reach from one or several selected source segments. It returns temporary text summaries in the information panel and draws the reachable subnetwork as a Reach by Selection layer.