Building Change Polygons for Turkiye Earthquake Recovery Effort

Overview
Maxar Technologies has utilized building segmentation models applied to Maxar's Analysis Ready Data (ARD) 
in order to derive regions of building change for areas of interest with regard to the February 6, 2023 
Turkiye earthquake.  The building change polygons indicate "removed building," "new building," 
"building to building," or "building change" areas. The files are split between UTM zones 36 and 37. 

Files
36_Feb11_vis_change.gpkg
37_Feb11_vis_change.gpkg  

Attributes
bdate:  the before date of the ARD image pair used to derive the change polygon
adate:  the after date of the ARD image pair used to derive the change polygon
bcid:  the before catalog ID of the ARD image pair used to derive the change polygon
acid:  the after catalog ID of the ARD image pair used to derive the change polygon
chtype: "build" (building) for all change polygons provided
chdesc: "nch" for building to building polygon, "rem" for removed building, "new" for new building,
        "och" for building change, and "nodata" for a region that didn't have matching data or had cloud or cloud shadow occlusion
quadkey:  the quadkey correspdonding to the ARD pair
utm:  the UTM zone
conf_seg_mean:  for "nch", "rem", "new" this is the mean of the probability change map over the 
                polygon; for "och" it is the percent change in the number of building segmentation 
                output pixel over a given threshold for the polygon

Notes
The change polygons are not building footprints, but derived regions of change.  The following are known 
reasons inaccurate results could occur.  Building detection is not as accurate in snowy regions, therefore 
affecting the change polygon result.  Image misalignment can cause false new building and removed building 
nearby each other; this is more prevalent in hilly regions.  Extreme tall building lean in the imagery can also affect results.

License
Creative Commons Attribution Non-Commercial 4.0 license (CC BY-NC 4.0)