Project creation options
The new project interface allows several categories of new information to be captured to set up a new mapping project. The top Project details section manages basic metadata.
The Backend section allows the selection of the spatial backend. There are three available backends: the standalone Spatialite GIS engine, the tethered PostGIS engine, and the Image backend.
The default Spatialite backend stores geospatial information directly in a database on the iPad, for easy use in offline scenarios (especially the field). This backend is mostly feature-complete, but many spatial operations (especially topology) are relatively slow. This makes it a poor choice for large mapping projects. Work is ongoing to remove some of these limitations, especially as the capabilities of iOS devices improve.
Choosing a spatial reference frame
The choice of spatial reference frame is important in all GIS applications, and Mapboard GIS has full support for the wide variety of spatial reference systems in common use. Reference systems prioritize validity and accuracy for different use cases and parts of the world (the Spatialite documentation has a good primer).
We are working on a helper to set the "correct" SRID for typical regional mapping projects. However, until this is finished, you must find and set the SRID yourself.
The default spatial reference, SRID
longitude/latitude relative to the WGS84 datum, is acceptable globally, but using a more
locally-relevant datum can improve the speed and accuracy of GIS calculations. For
instance, a UTM projection
is the standard for many regional and local applications.
The PostGIS backend
With the PostGIS backend, the application talks to a remote server (usually on a local network, although in principle internet locations can also be used), where all spatial operations are handled. This enables faster processing, data security, and collaborative mapping.
In PostGIS mode, spatial reference information and feature classes are managed on the server, so they are not configured within the app.
The Image backend
The Image backend is a stripped-down version of Spatialite mode that supports digitization atop a static image in pixel coordinates. This can help support processes such as annotating field images for later feature extraction from 3D models.
Some presently unwieldy aspects of the image mode, such as the restriction to a single image per project, may be addressed in future updates. Leave some feedback if you'd like to suggest improvements.