add conversion.py #correction

data_processing/conversion.py

@@ -0,0 +1,34 @@
+import rasterio as rio 
+import geopandas as gpd
+from rasterio.features import shapes
+
+def instance_mask_to_gdf(
+        instance_mask,
+        transform = None,
+        crs=None
+        ):
+    """
+    Input:
+        - instance_mask : np.array of shape (H,W), where each instance is labeled by a unique id/number
+        - transform : geospatial transform of the raster - default is None
+        - crs : crs of the raster - default is None
+    Output:
+        - GeoDataFrame of the shapes projected to the specified crs using the transform
+    """
+
+    #transform should be Identity if None is provided
+    transform = rio.transform.IDENTITY if transform is None else transform
+
+    all_shapes = shapes(instance_mask,mask=None,transform=transform)
+    data = [
+            {'properties' : {'id' : v} , 'geometry' : s} for i,(s,v) in enumerate(all_shapes) if v!=0
+    ]
+
+    if len(data) == 0:
+        ##return empty dataframe
+        return gpd.GeoDataFrame(columns=['id','geometry'], geometry='geometry',crs=crs)
+
+    gdf = gpd.GeoDataFrame.from_features(data,crs=crs)
+    gdf = gdf.dissolve(by='id')
+
+    return gdf