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.

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