some modern updates

contours/Makefile

@@ -26,7 +26,7 @@ db/contour_%: contour_%.gpkg db/.ready
 	touch $@
 
 contour_%.gpkg: all.tif
-	gdal_contour -a z -nln $(basename $@) -i $(subst _,.,$*) -a z $^ $@
+	gdal_contour -nln $(basename $@) -i $(subst _,.,$*) -a z $^ $@
 
 ifeq ($(VARIANT),2009)
 all.tif: all.vrt all.xyz
@@ -51,7 +51,7 @@ all.xyz: $(XYZ)
 
 .INTERMEDIATE: $(XYZ)
 %.xyz: %.zip
-	unzip -qq -c $< $@ | \
+	7z x -so $< $@ | \
 		./clip-$(VARIANT).awk $(addprefix -v ,$(BOUNDS)) | \
 		$(SORT) > $@