Update app.py

app.py

@@ -22,33 +22,46 @@ PAR_POLY=[(115.,5.),(115.,15.),(120.,21.),(120.,25.),(135.,25.),(135.,5.)]
 NEIGHBOR_COUNTRIES=["Philippines","Taiwan","Vietnam","Malaysia","Indonesia",
                     "China","Japan","Brunei","Palau"]
 SLIDER="https://slider.cira.colostate.edu"
+ZOOM=3  # tile zoom level for regional crop (0=full disk thumbnail, higher=sharper, more tiles)
 
-# --- Himawari full-disk geostationary projection (for cropping to DISPLAY_BBOX) ---
+# --- Himawari full-disk geostationary projection ---
 _HIMA_PROJ = Proj(proj='geos', h=35785863.0, lon_0=140.7, a=6378137.0, b=6356752.3, sweep='x')
 _FULL_DISK_EXTENT = 5500000.035308  # meters, half-width/height of full-disk image
 
-def _lonlat_to_fulldisk_px(lon, lat, img_w, img_h):
+def _lonlat_to_frac(lon, lat):
     x, y = _HIMA_PROJ(lon, lat)
-    px = (x + _FULL_DISK_EXTENT) / (2*_FULL_DISK_EXTENT) * img_w
-    py = (_FULL_DISK_EXTENT - y) / (2*_FULL_DISK_EXTENT) * img_h
-    return px, py
+    fx = (x + _FULL_DISK_EXTENT) / (2*_FULL_DISK_EXTENT)
+    fy = (_FULL_DISK_EXTENT - y) / (2*_FULL_DISK_EXTENT)
+    return fx, fy
 
-def _crop_resize_to_region(full_disk_arr):
-    h, w = full_disk_arr.shape
+def _bbox_frac_range():
     lon_min, lat_min, lon_max, lat_max = DISPLAY_BBOX
     corners = [(lon_min,lat_min),(lon_min,lat_max),(lon_max,lat_min),(lon_max,lat_max)]
-    xs, ys = [], []
+    fxs, fys = [], []
     for lon, lat in corners:
-        px, py = _lonlat_to_fulldisk_px(lon, lat, w, h)
-        xs.append(px); ys.append(py)
-    x0, x1 = max(0,int(min(xs))), min(w,int(max(xs)))
-    y0, y1 = max(0,int(min(ys))), min(h,int(max(ys)))
+        fx, fy = _lonlat_to_frac(lon, lat)
+        fxs.append(fx); fys.append(fy)
+    return min(fxs), max(fxs), min(fys), max(fys)
+
+def _crop_resize_to_region(full_disk_arr):
+    """Fallback: crop the single full-disk zoom-0 image (low-res)."""
+    h, w = full_disk_arr.shape
+    fx0, fx1, fy0, fy1 = _bbox_frac_range()
+    x0, x1 = int(fx0*w), int(fx1*w)
+    y0, y1 = int(fy0*h), int(fy1*h)
+    x0,x1 = max(0,x0), min(w,x1); y0,y1 = max(0,y0), min(h,y1)
     crop = full_disk_arr[y0:y1, x0:x1] if (x1>x0 and y1>y0) else full_disk_arr
-    img = Image.fromarray((np.clip(crop,0,1)*255).astype(np.uint8))
-    img = img.resize((W,H), Image.Resampling.BILINEAR)
+    img = Image.fromarray((np.clip(crop,0,1)*255).astype(np.uint8)).resize((W,H), Image.Resampling.BILINEAR)
     return np.array(img, dtype=np.float32)/255.
 
-# --- Country borders/coastlines (drawn at render time, same approach as Colab script) ---
+def _bbox_tile_range(zoom):
+    n = 2**zoom
+    fx0, fx1, fy0, fy1 = _bbox_frac_range()
+    col0,col1 = max(0,int(fx0*n)), min(n-1,int(fx1*n))
+    row0,row1 = max(0,int(fy0*n)), min(n-1,int(fy1*n))
+    return row0,row1,col0,col1,n
+
+# --- Country borders/coastlines ---
 def _fetch_geojson():
     try:
         return requests.get(
@@ -126,9 +139,53 @@ def fetch_slider_raw(ts, product="band_13"):
     img=Image.open(io.BytesIO(r.content)).convert("L")
     return np.array(img,dtype=np.float32)/255.
 
+def fetch_slider_region(ts, zoom=ZOOM, product="band_13"):
+    row0,row1,col0,col1,n = _bbox_tile_range(zoom)
+    date_path=f"{ts[:4]}/{ts[4:6]}/{ts[6:8]}"
+    tiles={}
+    tile_h=tile_w=None
+    for row in range(row0,row1+1):
+        for col in range(col0,col1+1):
+            url=f"{SLIDER}/data/imagery/{date_path}/himawari---full_disk/{product}/{ts}/{zoom:02d}/{row:03d}_{col:03d}.png"
+            try:
+                r=requests.get(url,timeout=10)
+                r.raise_for_status()
+                img=Image.open(io.BytesIO(r.content)).convert("L")
+                arr=np.array(img,dtype=np.float32)/255.
+                tiles[(row,col)]=arr
+                if tile_h is None: tile_h,tile_w=arr.shape
+                print(f"TILE z{zoom} {row:03d}_{col:03d} OK {arr.shape}")
+            except Exception as e:
+                print(f"TILE z{zoom} {row:03d}_{col:03d} FAILED: {e}")
+    if not tiles:
+        raise RuntimeError(f"No tiles fetched at zoom {zoom}")
+
+    n_rows=row1-row0+1; n_cols=col1-col0+1
+    mosaic=np.zeros((tile_h*n_rows,tile_w*n_cols),dtype=np.float32)
+    for (row,col),arr in tiles.items():
+        r_off=(row-row0)*tile_h; c_off=(col-col0)*tile_w
+        mosaic[r_off:r_off+tile_h,c_off:c_off+tile_w]=arr
+
+    fx0,fx1,fy0,fy1 = _bbox_frac_range()
+    mosaic_fx0,mosaic_fx1 = col0/n,(col1+1)/n
+    mosaic_fy0,mosaic_fy1 = row0/n,(row1+1)/n
+    mh,mw = mosaic.shape
+    px0=int((fx0-mosaic_fx0)/(mosaic_fx1-mosaic_fx0)*mw)
+    px1=int((fx1-mosaic_fx0)/(mosaic_fx1-mosaic_fx0)*mw)
+    py0=int((fy0-mosaic_fy0)/(mosaic_fy1-mosaic_fy0)*mh)
+    py1=int((fy1-mosaic_fy0)/(mosaic_fy1-mosaic_fy0)*mh)
+    px0,px1=max(0,px0),min(mw,px1); py0,py1=max(0,py0),min(mh,py1)
+    crop = mosaic[py0:py1,px0:px1] if (px1>px0 and py1>py0) else mosaic
+    img = Image.fromarray((np.clip(crop,0,1)*255).astype(np.uint8)).resize((W,H), Image.Resampling.BILINEAR)
+    return np.array(img, dtype=np.float32)/255.
+
 def fetch_slider(ts, product="band_13"):
-    raw = fetch_slider_raw(ts, product)
-    return _crop_resize_to_region(raw)
+    try:
+        return fetch_slider_region(ts, zoom=ZOOM, product=product)
+    except Exception as e:
+        print(f"Zoom {ZOOM} tile mosaic failed ({e}) -- falling back to full-disk zoom00")
+        raw = fetch_slider_raw(ts, product)
+        return _crop_resize_to_region(raw)
 
 def build_live_seq():
     ts=slider_ts()