Field-Map Data Collector

In this chapter:

• Adding polygons
• Polygonization
• Overlapping polygonization
• Non-overlapping polygonization
• Single steps of non overlapping polygonization
• Partial polygonization
• Other editing possibilities
• Handling multipolygons
• Export problem centroids
• Creating a grid of polygons
• Creating a buffer around a polygon
• Positioning circles inside polygons
• Importing polygons
• Check multiple centroids
• Unioning polygons
• Delete polygon(s) with centroid(s) or only polygons(s) and keep centroid(s)
• Setting polygon as a plot boundary
• Create polygonal mask

A polygonal layer is another type of GIS layer. It contains polygons or multipolygons represented by a set of lines, which create a boundary. Together with georeference, polygons are described by a perimeter and an area. For polygon labeling purposes Field-Map also works with centroids: unique points placed inside polygons. 

Polygon layers may contain polygons without topology (overlapping each other) or topologically clean (neighboring polygons share common border). 

The PolyShape built-in tool can be used for building topologically clean polygons.

Multipolygons (several geographically separated polygons with just one record in the database) and overlapping polygons are also supported. 

Field-Map also works with shapefiles which do not belong to “topological” GIS formats. For this reason Field-Map maintains boundary lines and centroids in separate line and point shapefiles. Points (centroids) and polygons (result of polygonization) together represent polygons in Field-Map.

As polygons "consist" of lines and points (centroids), some of tools and functions typical for line or point layers can be used also for respective objects existing in polygon layers. These are:

• point layer functions: Copy point to layer; Rotate label; Switch label OFF/ON; Get attribute values from points to polygons/polygons to centroids
• line layer functions: List Co-ordinates; Move or copy line(s) to layer

Note: Beginning with Field-Map X6 version you are not able to map lines into the polygonal layer anymore. For definition of borders of polygons during polygonization process use lines previously mapped into another line layer (see Non-overlapping polygonization chapter for details).