Algae Dataset
Every data hub, dataset, sensor, variable, paper and limitation in one tree — and for each: where it comes from, how far back it goes, how often it captures, why it belongs in a cholera study, and why it does not work everywhere.
- +DATA HUBSwhere the data physically comes from
- +DATASET TYPESgrouped by what kind of water they see
- +SITE-WISEwhat actually applies at each site
- +DURATION & CAPTURE CADENCEdaily · weekly · 10-day · 16-day · monthly
- +VARIABLESwhat is computed from the bands
- −LIMITATIONSwhy not — typed and severity-ranked
- +VALIDATION2 limitations · 1 critical
- +ACCESS6 limitations · 4 critical
- −SPATIAL6 limitations · 3 critical
- ·4 km pixel cannot resolve any inland water bodyCRITICALdataset AL01
- ·250 m works on the Meghna and nowhere else in this studyCRITICALdataset AL16
- ·Matlab shapefile contains 43 polygons from another upazilaCRITICALsite level
- ·300 m needs water wider than about 600 mHIGHdataset AL04
- ·1 km lake mask is unlikely to include your water bodiesHIGHdataset AL10
- ·Chakaria boundary has no internal unitsHIGHsite level
- +TEMPORAL7 limitations · 2 critical
- +ALGORITHMIC3 limitations · 1 critical
- +COVERAGE6 limitations · 1 critical
- +ATMOSPHERIC1 limitations
- +SPECTRAL2 limitations
- +PAPERSthe evidence, DOI-linked
SPATIAL limitations
CRITICAL 4 km pixel cannot resolve any inland water body spatial blocks Matlab blocks Dhaka
A single OC-CCI pixel is 16 km2. The widest reach of the Meghna is 6 km and every Dhaka lake is under 1 km across, so an inland pixel is dominated by land reflectance. The value returned is not a measurement of that water.
CRITICAL 250 m works on the Meghna and nowhere else in this study spatial blocks Dhaka
MODIS 250 m is the only genuinely daily inland option back to 2000, but it needs a wide channel. The Meghna at 2-6 km qualifies. Village ponds, shrimp ponds and Dhaka lakes are all far below one pixel.
CRITICAL Matlab shapefile contains 43 polygons from another upazila spatial blocks Matlab
MATLAB_HDSS_AREA.shp holds 251 polygons across Matlab Uttar (112), Matlab Dakkhin (96) and Daudkandi (43). Daudkandi is in Cumilla district, outside the HDSS. 42 of those 43 sit in Block E, so extracting without filtering leaves Block E 56 percent contaminated with no matching population denominator.
HIGH 300 m needs water wider than about 600 m spatial blocks Dhaka
A 300 m pixel needs at least two clean pixels across the water body to avoid land contamination. The Matamuhuri estuary and the Meghna main channel qualify comfortably. In Dhaka only the widest reaches of the Buriganga and Shitalakshya come close, and even there the pixels are mixed - Hatirjheel is roughly 200 m at its widest, so every lake is out. The catalogue records Dhaka as MARGINAL rather than impossible for this reason.
HIGH 1 km lake mask is unlikely to include your water bodies spatial blocks Chakaria blocks Matlab
ESA CCI Lakes covers a fixed global lake list at 1 km. Chakaria's coastal lagoons and Matlab's beels are almost certainly not in it, and Dhaka's lakes are borderline.
HIGH Chakaria boundary has no internal units spatial blocks Chakaria
HDSS_Chakaria_Boundary.shp is a single polygon with only OBJECTID, Shape_Leng and Shape_Area. The 11 unions in the config are not in the file. The east side is hilly and the west is coastal lowland with the shrimp-pond belt - completely different hydrology and salinity.