Chart Overview
You can explore observation data with interactive charts.
Temporal Changes
Temporal changes produce charts summarizing the observation data that meet the current criteria and hence presented on the map. There are three views of temporal periods each of which provide changeable temporal scales.
- Time series
- Seasonal
- Diel
< Time Series >
changes of the summary over time. Available temporal scales are:
- Century
- Decade
- Year
- Year-month
- Year-month-day
< Seasonal >
Seasonal or monthly changes of the summary. Available temporal scales are:
- Four seasons
Spring: March/April/May
Summer: June/July/August
Fall: September/October/November
Winter: December/January/February - 12 months
< Diel >
Changes of the summary per hour. Diel charts are available when the points layer is on.
A diel summary includes those records having a timestamp (observation date and time) at a hour or finer scale. Records with only date (no time) are excluded.
< Variables of the y-axis >
| Variable | Description |
|---|---|
| #records | The number of records that meet the current criteria. This does not indicate any scientific implications. |
| #animals | The sum of the group / herd size. Note that there are records that do not provide the count. For these, the count is assumed to be one (1) to be conservative. |
| #species | The number of distinct taxa across all levels of the taxonomic hierarchy. If the animal was identified at a higher taxon level (e.g. genus or family), this taxon is also counted. Thus, the number of species could be slightly overestimated when, for example, there are two records one of which identified the animal as Kogia and the other as Kogia sima if the first one was actually Kogia sima (but the observer wasn't able to pinpoint it as Kogia sima). |
| Diversity indices | Three diversity indices, Shannon, Simpson, Hurlbert's, are calculated and visualized with individual lines. |
| #calls | The number of detections. This is for passive acoustic monitoring data only and does not take in any non-PAM records. |
< Effort and Animal Tracks >
When the points layer is on, you can add a summary of survey effort or animal tracks to the chart as a series. If effort is added, only those records from datasets that are accompanied by effort (e.g. line transect surveys) are taken in the summary calculation.
< Chart options >
a. Hide temporal gaps
When [Time series] is selected, this option omits the periods where no observation data exists. Thus, the chart usually becomes less wide than the one with a continuous time.
b. Each species as a series
When this option is checked, the chart produces individual lines for a group of five species. Species are grouped based on the number chosen for the Y-axis (e.g. #records or #animals) and you can move higher or lower in terms of the number by clicking "Next" or "Prev" link below the legend.
Oceanographic Variables
OBIS-SEAMAP samples oceanographic variables using publicly available remote sensing sattelite imagery against all point observation records in the OBIS-SEAMAP database. The sampled oceanographic variables are visualized with line charts and histograms along with the temporal change charts.
Currently, the following variables are available.
| Sea Surface Temperature (OISST) | |
|---|---|
| Source | Optimum Interpolation Sea Surface Temperature v2.0 via GEE |
| Availability | 1981-09-01 through Present |
| Averaging | DAY, 8DAYS, MONTH, YEAR |
| Cell size | 0.25 arc degrees |
| Unit | Degree Celsius |
| Sea Surface Temperature (MODIS) | |
| Source | MODIS (Aqua) via GEE |
| Availability | 2002-07-04 through Present |
| Averaging | DAY, 8DAYS, MONTH, YEAR |
| Cell size | 500 meters |
| Unit | Degree Celsius |
| Sea Surface Temperature (HYCOM) | |
| Source | HYCOM via GEE |
| Availability | 1992-10-02 through Present |
| Averaging | MONTH, YEAR |
| Cell size | 0.08 arc degrees |
| Unit | Degree Celsius |
| Sea Surface Height | |
| Source | Aviso Global DT-Upd Merged MADT SSH |
| Availability | 1992-288 through 2010-090 |
| Averaging | Weekly |
| Cell size | 0.25 degree |
| Unit | cm |
| Notes | When the temporal scale is set to "month", a weekly average that the first day of the month belongs to is picked up. |
| Chlorophyll a (MODIS) | |
| Source | MODIS (Aqua) via GEE |
| Availability | 2002-07-04 through Present |
| Averaging | DAY, 8DAYS, MONTH, YEAR |
| Cell size | 500 meters |
| Unit | mg*m-3 |
| Chlorophyll a (SeaWiFS) | |
| Source | SeaWiFS via GEE |
| Availability | 1997-09-04 through 2010-12-11 |
| Averaging | DAY, 8DAYS, MONTH, YEAR |
| Cell size | 10000 meters |
| Unit | mg*m-3 |
| Salinity | |
| Source | HYCOM via GEE |
| Availability | 1992-10-02 - Present |
| Averaging | MONTH, YEAR |
| Cell size | 0.08 degree |
| Unit | psu |
| Bathymetry (S2004) | |
| Source | S2004 (compilation of GEBCO and Smith/Sandwell) |
| Availability | - |
| Averaging | - |
| Cell size | 1 arc-minute |
| Unit | Meters. Depths represented as positive values. |
| Bathymetry (ETOPO1) | |
| Source | ETOPO1 via GEE |
| Availability | - |
| Averaging | - |
| Cell size | 1 arc-minute |
| Unit | Meters |
To learn more about how to use the sampled oceanographic variables, see the Oceanographic Variables available on Mapping Tool.
