Saudi shoreline change from the 1990s to the 2020s: 5,741 transects with change rates

Where the Saudi coast has eroded or advanced, and by how many metres a year: 5,741 transects every 500 m along 4,473 km of Red Sea and Arabian Gulf coast, each with the shoreline shift between the two epochs, its annual rate and status, plus a per-governorate table.

27.8% of transects are eroding.

Who it is for

Coastal planning and development bodies, environmental and engineering consultancies, coastal tourism projects, and geography and environment departments.

Method: what we add to the raw data

• The water edge was measured in two epochs from satellite imagery, the early 1990s and the early 2020s, using the modified normalised difference water index.
• The median of four clear summer images per epoch was used, not a single scene, so tide, a stormy day or a cloud cannot mislead it.
• Transects perpendicular to the coast were drawn every 500 m, and the water-edge crossing measured on each in both epochs.
• Change is the difference between the two positions in metres; the rate divides it by the years between epoch midpoints, with positive meaning seaward advance.
• Only the sea coast is measured: it is separated from the land border by testing whether sea actually lies beside each point on the boundary, not by touching neighbouring polygons, which do not align exactly and would leave land border counted as coast.
• Measurement uses a conformal conic projection centred on the Kingdom rather than a single UTM zone, because the coasts run from 16 to 29 degrees north across four zones.

Product details

Spatial layers

• transect_change — lines, 5,741: Transects with shift and rate
• shoreline_points_2020s — points, 5,741: Water-edge positions in the later epoch
• governorates_shoreline — polygons, 29: Coastal governorates with change rate

Tables

• D128_transects.csv — 5,741 rows: Transects table
• D128_governorates_shoreline.csv — 29 rows: Change per governorate

Limitations

• The water edge in imagery is not a surveyed shoreline: it varies with tide and beach slope, so it suits trend and comparison, not fixing a property boundary.
• The image cell is 30 m, so change under about ten metres sits within error, which is why transects below half a metre per year are treated as stable.
• The two epochs are multi-year medians, not single years, and change may have occurred within part of the period.
• Reclamation and built structures appear as advance that is not natural accretion, and Saudi coasts carry extensive reclamation at ports and industrial cities; the user tells them apart by location.
• Transects without enough imagery in either epoch are not included.
• The coast length measured here comes from a digital boundary sampled every 200 m, longer than commonly cited figures measured at a coarser scale; coastline length grows as measurement gets finer.
• This is trend analysis, not coastal dynamics modelling: waves, sediment, currents and tide are not included.

FAQ

How long does delivery take?

Up to 6 hours after payment is confirmed.

How long does the download link last?

24 hours, and it is renewed free on request.

Can I get a refund?

Digital products are not refundable once downloaded — unless the file is defective or does not match the description, in which case it is replaced or fully refunded.

What does the licence allow?

Commercial use is allowed for you and the organisation you buy for; resale or redistribution is not.