I am creating a small land use map, as an exercise for visual image interpretation. I created a shapefile and started digitising polyogons with the polygon tool. The problem is that some of my polygons are automatically simplified/generalised. Some of the vertices disappear as soon as I finish sketch, which makes my map not very accurate.
Then, I also noticed that merging the polygons simplifies them. I just select polygons and click merge, then I notice gaps between them, some of the vertices having disappeared.
I searched the ArcGIS help, as well as online, to see if there are any editing options that I could change to disable this automatic simplification / generalisation, but I could not find any clear answers, only info about tools that can be used to deliberately achieve this effect. I just want ArcMap to leave my vertices where I put them.
This is my first editing attempt in ArcMap 10.2. I haven't come across this problem in ArcMap 10.1.
EDIT: I am including some further information.
From my Data frame properties:
Map units: Unknown Units
Display: Decimal degrees
Current coordinate system: No coordinate system.
As background image for my polygon shapefile I am using a scanned true color photo (23X23 cm), scale 1:10,000, in the form of a tiff file, with the following properties:
Columns and Rows: 5959, 5573
Cell Size (X.Y): 4.2333418e-005, 4.2333418e-005
Spatial Reference: undefined
Regarding the tolerance, the only types of tolerance that I have set in ArcGIS so far are the "snapping tolerance" and the "sticky move tolerance". I assume that in your comments you are talking about the X,Y tolerance, about which the ArcGIS Help says it has a default value of 0.001 meters (?)