From 6bd4e49c4acfe27ad28e6d0df6498c420061af3c Mon Sep 17 00:00:00 2001
From: BRAUN REMI <remi.braun@unistra.fr>
Date: Mon, 6 Mar 2023 12:33:21 +0100
Subject: [PATCH] OPTIM: Always use chunks when reading rasters #58

---
 CHANGES.md           |  6 ++++++
 docs/sar.md          | 14 +++++++-------
 eoreader/env_vars.py |  5 +++++
 eoreader/utils.py    |  9 ++++-----
 4 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index 2a8996cf..87f4e912 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,11 @@
 # Release History
 
+## 0.YY.Z (2023-MM-DD)
+
+### Other
+
+- OPTIM: Always use chunks when reading rasters ([#58](https://github.com/sertit/eoreader/issues/58))
+
 ## 0.19.2 (2023-02-23)
 
 ### Bug Fixes
diff --git a/docs/sar.md b/docs/sar.md
index b39120e8..c7ac1dc1 100644
--- a/docs/sar.md
+++ b/docs/sar.md
@@ -31,16 +31,16 @@ mostly because SNAP doesn't handle them.
 | `Capella`                           | SICD, SIDD, CPHD                     | ❌       |
 | `COSMO-Skymed`                      | SCS                                  | ✅       |
 | `COSMO-SkyMed` 1st Generation       | DGM                                  | ✅       |
-| `COSMO-SkyMed` 2nd Generation       | DGM                                  | ⚠️      |
-| `COSMO-SkyMed`                      | GEC, GTC                             | ⚠️      | 
+| `COSMO-SkyMed` 2nd Generation       | DGM                                  | ⚠       |
+| `COSMO-SkyMed`                      | GEC, GTC                             | ⚠       | 
 | `ICEYE`                             | SLC                                  | ✅       |
 | `ICEYE`                             | GRD                                  | ✅       | 
 | `ICEYE`                             | ORTHO                                | 💤      |
-| `RADARSAT Constellation Mission`    | SLC                                  | ⚠️      | 
-| `RADARSAT Constellation Mission`    | GRC, GCC, GCD                        | ⚠️      |
+| `RADARSAT Constellation Mission`    | SLC                                  | ⚠       | 
+| `RADARSAT Constellation Mission`    | GRC, GCC, GCD                        | ⚠       |
 | `RADARSAT Constellation Mission`    | GRD                                  | ✅       | 
 | `RADARSAT-2`                        | SLC                                  | ✅       | 
-| `RADARSAT-2`                        | SGX, SCN, SCW,<br>SCF, SCS, SSG, SPG | ⚠️      |
+| `RADARSAT-2`                        | SGX, SCN, SCW,<br>SCF, SCS, SSG, SPG | ⚠       |
 | `RADARSAT-2`                        | SGF                                  | ✅       |
 | `Sentinel-1`                        | SLC                                  | ✅       | 
 | `Sentinel-1`                        | GRD                                  | ✅       |
@@ -50,11 +50,11 @@ mostly because SNAP doesn't handle them.
 | `SAOCOM-1`                          | GTC                                  | ✅       |
 | `TerraSAR-X`, `TanDEM-X`, `PAZ SAR` | SSC                                  | ✅       | 
 | `TerraSAR-X`, `TanDEM-X`, `PAZ SAR` | MGD                                  | ✅       |
-| `TerraSAR-X`, `TanDEM-X`, `PAZ SAR` | GEC                                  | ⚠️      |
+| `TerraSAR-X`, `TanDEM-X`, `PAZ SAR` | GEC                                  | ⚠       |
 | `TerraSAR-X`, `TanDEM-X`, `PAZ SAR` | EEC                                  | ✅       |
 
 ✅: Tested   
-⚠️: Never tested, **use it at your own risk!**  
+⚠: Never tested, **use it at your own risk!**  
 ❌: Not handled   
 💤: Waiting for the release  
 
diff --git a/eoreader/env_vars.py b/eoreader/env_vars.py
index 7365693b..b91aa85b 100644
--- a/eoreader/env_vars.py
+++ b/eoreader/env_vars.py
@@ -55,3 +55,8 @@
 """
 If set and  :code:`dask` is installed, EOReader will read products as dask arrays instead of numpy arrays.
 """
+
+TILE_SIZE = "EOREADER_TILE_SIZE"
+"""
+If set, overrides the default tile size used in chunking (2048 by default)
+"""
diff --git a/eoreader/utils.py b/eoreader/utils.py
index 3501fa07..8d5574db 100644
--- a/eoreader/utils.py
+++ b/eoreader/utils.py
@@ -37,7 +37,7 @@
 
 from eoreader import EOREADER_NAME
 from eoreader.bands import is_index, is_sat_band, to_str
-from eoreader.env_vars import USE_DASK
+from eoreader.env_vars import TILE_SIZE, USE_DASK
 from eoreader.exceptions import InvalidProductError
 from eoreader.keywords import _prune_keywords
 
@@ -159,10 +159,9 @@ def read(
     """
     window = kwargs.get("window")
 
-    if use_dask():
-        chunks = True
-    else:
-        chunks = None
+    # Always use chunks
+    tile_size = os.getenv(TILE_SIZE, 2048)
+    chunks = [tile_size, tile_size]
 
     try:
         # Disable georef warnings here as the SAR/Sentinel-3 products are not georeferenced