topic Re: Understanding snap to grid in ArcGIS Pro Questions

Understanding snap to grid

GerardAshton — Fri, 27 Oct 2023 19:47:38 GMT

Most of my computer drawing experience is from the integrated circuit industry. I am used to a drawing having an origin and X, Y coordinates that cover the entire drawing. This would be similar, in the US, to using a state plane coordinate system as the horizontal coordinate system.

I am used to being able to enable a snap grid. In an integrated circuit, one might choose grid spacing of 1 micrometer; in ArcGIS Pro at a particular moment, I might choose a grid spacing of 10 meters. If I did this, I would be able to start a line at coordinates 1010, 2030, but not 1011.7, 2029.4. If I clicked to put down the start point, the start point would be on the nearest grid intersection. All of this refers to world units, not the number of pixels on a screen, or not the distance you would measure if you held a ruler to the screen. And if I moved an object, the reference point of the object would be forced to land at a grid intersection.

Can someone explain how snap to grid works in ArcGIS Pro desktop. I've experimented with it and it just makes no sense to me.

Re: Understanding snap to grid

DavidSolari — Fri, 27 Oct 2023 20:01:07 GMT

GIS is primarily concerned with the locations of object relative to a fixed reference. Or "the earth" to be specific. As such, the grid options are all pinned to the origin of your map's coordinate system, in the units of said system.

That said, an option to center the grid relative to the start of a sketch seems like a handy function, hit up the Ideas area and it might get implemented down the road.

Re: Understanding snap to grid

GerardAshton — Fri, 27 Oct 2023 20:32:37 GMT

DavidSolari wrote "the grid options are all pinned to the origin of your map's coordinate system, in the units of said system." That's exactly what I want. The problem I'm having is I can't figure out how to set the snapping options and manipulate the cursor to make ArcGIS Pro behave as I expect. I'm thinking of working in a map, not in a layout.

Re: Understanding snap to grid

GerardAshton — Fri, 27 Oct 2023 21:52:27 GMT

I tried resetting the snapping options, and then setting the grid the way that seemed right to me. Now it works as I expect.