I'm in need of a robust mobile application and an associated web portal. The application's main function will be to collect varying types of data, in the form of text, images, and GPS locations. This collection should occur through a mix of manual input, camera capture and GPS tracking options.

The collected data should then be stored in a Cloud database which will be directly linked and accessible through a web portal. This portal must include these key features:

- Data visualization capabilities: to display the collected data in intuitive ways, aiding quick understanding and analysis of the information gathered, primarily using GIS mapping and filters/overlays.

- User authentication: to ensure secure access to the data.

- Data filtering: to help streamline data analysis and reporting, the portal should be able to sort and filter the data based on various parameters.

Ideal freelancers for this project will have experience in mobile app development, preferably with a focus on data collection. Skills in developing interactive web portals are also desired, along with knowledge in secure data storage and management practices. A deep understanding of data visualization and user authentication systems will be a definite plus.

Update with more details:

Many thanks for responding to my project. In order to reduce the number of applicants down to the most appropriate, please respond to these additional criteria:

1: The App will allow users to record sightings of various species of fish and marine life, using drop down lists for ease of database integration. There will be up to 15 different genres of sightings: vessel behavior, pollution, fish species, shoreline development etc.

2: Using the GPS coordinates of each sighting/event, the web portal will display each event on a GIS map. The maps will be of specific Caribbean islands where the app is deployed. Filters will allow users to see groupings of specific fish species, for instance, or sightings of whales. Each filter will be an overlay using GIS maps. Data from the Cloud will be uploaded to the portal on a daily basis. Each sighting/event will be displayed on the map as a dot, with the ability to drill down to see the underlying data and report.

3: In the event of numerous sightings of a specific species, heat maps need to be generated, again using GIS.

Please respond with specific examples of your experience integrating GIS mapping into data visualization applications.