Add license terms for cache API

Author: AlexeyPechnikov

README.md

@@ -17,6 +17,10 @@ The previous-generation [PyGMTSAR](https://github.com/AlexeyPechnikov/pygmtsar)
 
 For funded academic, institutional, or professional use of the insardev package, see [insardev/SUBSCRIBE](https://github.com/AlexeyPechnikov/InSARdev/blob/main/insardev/SUBSCRIBE). The BSD-licensed insardev_pygmtsar and insardev_toolkit do not require subscription.
 
+## API Services
+
+The Cache APIs at insar.dev provide fast access to Sentinel-1 data via NASA ASF and Copernicus, and NASA NISAR data. Free for non-commercial use; license required for funded academic, institutional, or professional use. See [insardev/LICENSE](./insardev/LICENSE) for terms.
+
 ## Features
 
 - **Per-burst/swath processing** — each Sentinel-1 TOPS burst and NISAR swaths processed independently on a geocoded grid, no frame stitching required

insardev/LICENSE

@@ -235,3 +235,23 @@ Not permitted without written permission:
   - Commercial redistribution
 
   Contact: alexey@pechnikov.dev
+
+---
+
+API SERVICES
+
+The Cache APIs at insar.dev (Sentinel-1 via NASA ASF and Copernicus, and NASA
+NISAR) are subject to the same licensing terms as the insardev library.
+
+Free for non-commercial use:
+  - Personal learning and self-education
+  - Unfunded academic coursework, thesis, or dissertation work
+  - Hobby projects with no commercial intent
+  - Teaching and classroom instruction
+
+License required for funded academic, institutional, or professional use:
+  - Grant-funded, institutional, or government-funded research
+  - Business, consulting, or professional services
+  - Corporate or organizational projects
+
+For licensing, contact: alexey@pechnikov.dev

insardev_toolkit/insardev_toolkit/ASF.py

@@ -237,6 +237,8 @@ def __init__(self, username=None, password=None):
         """
         self.username = username
         self.password = password
+        if username is None:
+            print("NOTE: Using insar.dev Cache API. Free for non-commercial use; license required for funded academic, institutional, or professional use.")
 
     def _get_asf_session(self):
         """Get authenticated session for ASF downloads.
@@ -414,11 +416,11 @@ def download(self, basedir, bursts, polarization=None, frequency=None, bbox=None
             - None: S1 uses pol from name, NISAR downloads all available
             - 'VV': Download only VV (S1) or 'HH' (NISAR)
             - ['VV', 'VH']: Download both polarizations
-        frequency : str, required for NISAR
-            Which frequency band to download (NISAR stores two frequencies with different resolutions):
-            - 'A': frequencyA (20MHz bandwidth, ~7m range resolution, primary InSAR)
-            - 'B': frequencyB (5MHz bandwidth, ~25m range resolution, 4x less data)
-            To download both frequencies, call download() twice with different output directories.
+        frequency : str or list, required for NISAR
+            Which frequency band(s) to download (NISAR stores two frequencies with different resolutions):
+            - 'A': frequencyA (20MHz bandwidth, ~7m range resolution, ~10GB per scene)
+            - 'B': frequencyB (5MHz bandwidth, ~25m range resolution, ~1.5GB per scene)
+            - ['A', 'B']: Both frequencies in same file (~14GB per scene)
         bbox : tuple or None, optional (NISAR cache proxy only)
             Bounding box in WGS84 coordinates: (west, south, east, north).
             When provided, only downloads aligned blocks covering the bbox.
@@ -480,10 +482,10 @@ def download(self, basedir, bursts, polarization=None, frequency=None, bbox=None
         # Require explicit frequency for NISAR to prevent accidental large downloads
         if nisar_granules and frequency is None:
             raise ValueError(
-                "NISAR data requires explicit frequency='A' or 'B' parameter.\n"
-                "  frequency='A': 20MHz bandwidth (~7m range resolution, primary InSAR)\n"
-                "  frequency='B': 5MHz bandwidth (~25m range resolution, 4x smaller)\n"
-                "To download both frequencies, run download() twice with different output directories."
+                "NISAR data requires explicit frequency parameter:\n"
+                "  frequency='B': 5MHz bandwidth (~25m res, ~1.5GB) - recommended for quick look\n"
+                "  frequency='A': 20MHz bandwidth (~7m res, ~10GB) - full resolution InSAR\n"
+                "  frequency=['A','B']: Both frequencies in same file (~14GB)"
             )
 
         # Check if any downloads needed BEFORE creating session (avoid network call)
@@ -1529,14 +1531,13 @@ def download_nisar_granule(granule_id, basedir, polarizations, skip_exist, debug
                     print(f"WARNING: Polarizations {missing} not available in {granule_id}")
 
             # Update frequency download flags based on actual availability
-            download_freq_a = frequency is None or frequency == 'A'
-            download_freq_b = (frequency is None or frequency == 'B') and has_freq_b
+            # Normalize frequency to list for consistent checking
+            freq_list = [frequency] if isinstance(frequency, str) else frequency
+            download_freq_a = 'A' in freq_list
+            download_freq_b = 'B' in freq_list and has_freq_b
 
             if debug and position is None:
-                if frequency is None:
-                    freq_str = 'A+B' if has_freq_b else 'A'
-                else:
-                    freq_str = frequency
+                freq_str = '+'.join(f for f in freq_list if f == 'A' or (f == 'B' and has_freq_b))
                 print(f"NISAR {track}_{frame}: downloading {pols_to_download} (frequency{freq_str})")
 
             if layout != 'A':
@@ -2332,9 +2333,10 @@ def download_granule_via_cache(granule_id, position=None, shared_pbar=None, shar
                     if missing:
                         print(f"WARNING: Polarizations {missing} not available")
 
-                # Frequency flags
-                download_freq_a = frequency is None or frequency == 'A'
-                download_freq_b = (frequency is None or frequency == 'B') and has_freq_b
+                # Frequency flags - normalize to list for consistent checking
+                freq_list = [frequency] if isinstance(frequency, str) else frequency
+                download_freq_a = 'A' in freq_list
+                download_freq_b = 'B' in freq_list and has_freq_b
 
                 # Get chunk info for all pols
                 all_chunk_info = {}
@@ -2527,8 +2529,10 @@ def download_single_chunk(gid, offset, length):
                 pols = [p for p in (polarizations or avail_pols) if p in avail_pols]
                 has_freq_b = 'frequencyB' in swaths
                 freq_b_pols = [k for k in swaths['frequencyB'].keys() if k in ['HH','HV','VH','VV']] if has_freq_b else []
-                dl_a = frequency is None or frequency == 'A'
-                dl_b = (frequency is None or frequency == 'B') and has_freq_b
+                # Normalize frequency to list for consistent checking
+                freq_list = [frequency] if isinstance(frequency, str) else frequency
+                dl_a = 'A' in freq_list
+                dl_b = 'B' in freq_list and has_freq_b
 
                 # Pre-collect chunk info for all pols while h5 is open
                 all_chunk_info = {}

insardev_toolkit/insardev_toolkit/CDSE.py

@@ -324,6 +324,8 @@ def __init__(self, username=None, password=None):
         self.password = password
         self._session = None
         self._token_time = None
+        if username is None:
+            print("NOTE: Using insar.dev Cache API. Free for non-commercial use; license required for funded academic, institutional, or professional use.")
 
     @staticmethod
     def _normalize_polarization(polarization):