Inter-tidal mapping

An apparatus for mapping an inter-tidal area, comprising:

• a computer, configured to process a sequence of images of the inter-tidal area, obtained over a period of time at a range of different stages of the tide and a time at which each image was obtained, recorded on a data storage device so as to:
• create a measure of change with respect to time for an image location,
• determine an elevation for the location, based on a similarity between the measure of change at the location and the transitions from wet to dry at each elevation recorded in tidal data, wherein the tidal data comprises transitions with respect to time between wet and dry at each elevation;
• wherein determining the elevation comprises determining a measure of change with respect to time for the location, wherein the measure of change corresponds with the square of the gradient of the image value with respect to time for the location.

A method of mapping an inter-tidal area, comprising:

• obtaining, over a period of time, image data comprising:
• a sequence of images of the inter-tidal area at a range of different stages of the tide, and the time at which each image was obtained;
• determining an elevation of a location in the image, by correlating the changes in an image value over time at the location with tidal data comprising the elevation of the tide over the period of time, wherein the tidal data comprises the transitions, over the period of time, between wet and dry at each of a plurality of elevations;
• identifying whether the location stays wet or dry over the period of time;
• wherein at least one of the following applies:
• (a) the method further comprises determining a measure of change with respect to time for the location, and identifying the location as staying dry over the period of time by determining that the measure of change at the location, over the period of time, is below a threshold level;
• (b) the method further comprises determining a measure of change with respect to time for the at least one location, and identifying a location as staying wet over the period of time by determining that the frequency of changes in the image are above a threshold frequency;
• or
• (c) determining the elevation comprises determining a measure of change with respect to time for the location, wherein the elevation is determined based on a similarity between the measure of change at the location and the transitions at each elevation, and wherein the location is determined as staying wet or dry when the similarity between the measure of change and the transitions for each and every elevation is below a threshold level.

An apparatus for mapping an inter-tidal area, comprising:

• a computer, configured to process a sequence of images of the inter-tidal area, obtained over a period of time at a range of different stages of the tide and a time at which each image was obtained, recorded on a data storage device so as to:
• create a measure of change with respect to time for an image location,
• determine an elevation for the location, based on a similarity between the measure of change at the location and the transitions from wet to dry at each elevation recorded in tidal data, wherein the tidal data comprises transitions with respect to time between wet and dry at each elevation,
• identify whether the location stays wet or dry over the period of time;
• and at least one of:
• determine a measure of change with respect to time for the location, and identify the location as staying dry over the period of time by determining that the measure of change at the location, over the period of time, is below a threshold level;
• determine a measure of change with respect to time for the at least one location, and identify a location as staying wet over the period of time by determining that the frequency of changes in the image are above a threshold frequency;
• or
• in determining the elevation, determine a measure of change with respect to time for the location, wherein the elevation is determined based on a similarity between the measure of change at the location and the transitions at each elevation, and wherein the location is determined as staying wet or dry when the similarity between the measure of change and the transitions for each and every elevation is below a threshold level.

A non-transitory computer readable medium comprising software for mapping an inter-tidal area that, when loaded on a suitable computer, configures the computer to process a sequence of images of the inter-tidal area, obtained over a period of time at a range of different stages of the tide and a time at which each image was obtained, recorded on a data storage device so as to:

• create a measure of change with respect to time for an image location, and
• determine an elevation for the location, based on a similarity between the measure of change at each location and the transitions from wet to dry at each elevation recorded in tidal data, wherein the tidal data comprises transitions with respect to time between wet and dry at each elevation;
• identify whether the location stays wet or dry over the period of time;
• and at least one of:
• determine a measure of change with respect to time for the location, and identify the location as staying dry over the period of time by determining that the measure of change at the location, over the period of time, is below a threshold level;
• determine a measure of change with respect to time for the at least one location, and identify a location as staying wet over the period of time by determining that the frequency of changes in the image are above a threshold frequency;
• or
• in determining the elevation, determine a measure of change with respect to time for the location, wherein the elevation is determined based on a similarity between the measure of change at the location and the transitions at each elevation, and wherein the location is determined as staying wet or dry when the similarity between the measure of change and the transitions for each and every elevation is below a threshold level.