Digitizing in ArcMap

this is a brief demonstration of digitizing in arcmap 10.1 this is a common scenario where you want to be able to create a GIS feature whether it's a point a line or polygon from some existing data so in this case I've loaded a on line base map which is the Bing aerial photos but this could be lots of different things could be a topographic base map it could be a scan of an image of could be an air photo or an image of a an old historical map but the point is with the the original version of the data like this you don't have anything you can click on you can't add attributes it's just a picture of something and what we're going to do is create a feature from this by tracing on it all right so the first thing we need to do is make sure that we have our editor and snapping toolbars added to arcmap so in this case I've done this already but you can do it from the customize toolbars menu and then you would just select those two toolbars so editor and snapping once you have those then we have to create a feature class in which we can place the new features that we're going to create so I'm going to go to my file geodatabase here right click and select a new feature class so give it a name you don't have to give it an alias and then in ArcGIS you have to tell it which type of feature you want to create point line polygon and so on because you can't have these in the same feature class so we'll create some points click Next I'm going to use the UTM coordinate system that's appropriate for this area this is high park in Toronto so UTM zone 17n click Next I'll go with the default XY tolerance which in this case is one thousandth of a meter which is great and I'll go with the default configuration keyword and here's where you can add extra attributes if you like so in this case I could I'll just click on it give the attribute a name so that'll be the name of the field or the column that'll be added to the table and I'll go with the default which happens to be text with a length of 50 characters I'll select finish and this will create a new feature class that I can then use for digitizing okay so now I have got my empty future class for trees I can go to the editor toolbar and select start editing and that then activates many of the features available in the editor toolbar and one thing that may not be obvious at first glance is that we need to activate the create features pane which is the last icon on the right in the toolbar so if I click on that this creates or opens up a new pane called create features and you'll notice that it's already selected trees as my feature class and then below that we have construction tools so we can create a new point or create a point at the end of a line so I could then if I like let's do this I can go over and change the symbology for my trees so let's say I want to I'll search for tree here and go down and search for let's see this looks like a good symbol so I'll use that say ok and so with this selected for my points I can then if you'll notice that as I drag this around I hope you can see this in recording it's actually showing where that symbol would be created so if I wanted to digitize some of these trees I can just click where I want to place it like so and a point is created with the symbology that I've predetermined so here's my little tree canopy and I can do this as many times as I want and if I like as I'm editing if I go and select the attribute pane I can add the attribute while I'm digitizing so in this case this is my third tree I can click in the the null area here here and then type in my attributes so in this case I could put in say the the type of tree such as maple hit enter and now that attribute when I save it will be saved with the point that's associated with it so I can continue to do this all day long I could add another one if I wanted I could give that a name as well so let's say that this is going to be lets say a walnut tree and so on okay that's basically it so once you're done you have to go back to the editor toolbar and say you can just save edits if you want to save them as you go or if you're done you can say stop editing and if you haven't saved your edit so will ask you if you want to save them at that point so now I have a new feature class with my trees created inside it and remember that these points are actually infinitely small they don't have the actual outline of that symbol I just chose that symbol if I change it to something else it would have a different size or whatever so now I have my points so now if I wanted to I can create some lines so I'll create another feature class for some lines I'm just gonna show you lines and polygons so here let's call these paths these are going to be line features I'll use the same coordinate system as before them all the same settings and I won't bother with an attribute here so now when I'm creating my lines the main thing that you have to remember is or to think about is to what the sampling frequency is that you're going to use for these in other words these paths are all curved how am I going to to approximate the curve or the shape of each of these objects so I'll go back and start editing here and I'll select the create features pane and you'll notice that my trees are still there but I'm now going to select paths and it's the construction tool I'm going to use it's just a line and I'm going to then start my line wherever I want that line segment to begin like so and then you essentially just click to create a vertex which is a point at which the line changes direction and so I could go on like this and like I said you have to decide how many vertices you want to use to describe that line here I've got a few I'm doing a reasonably decent job and then we get to the end of the line segment that you want to create you can double click to finish that line segment okay I could do more of these but essentially it's the same process if I wanted to I could snap to an existing line whoops so or I could edit a vertices or a vertex so if I for example zoom in here and say that mmm that line isn't exactly where I wanted it I could select edit vertices on this toolbar and then I can for example move a vertex to a new location and say finish sketch and it will actually move that I could then also do things like add a vertex using the Edit vertices toolbar here that pops up so if I click add a vertex and then click on the line that creates a new vertex so that gives me a new place where I can then change the direction of that line so I could drag that new vertex and then say finish sketch and so now I can so I can move existing vertices I can add a vertex I can delete one and this gives you some fine-tuning control over the placement of particular objects on your line all right so I'll say stop editing and it will ask me if I want to save them I'll say yes and we'll zoom out again and so there is my existing path we'll just make it a little more visible here so that's the the path that I digitized lastly we're going to a polygon so I'll create yet another feature class and this will be we'll just call this Park and it's already set to polygon features I'll stay next to use the same settings as my other ones and finish and now I will be able to create Park polygons so these might be within each path if I'm using the path to describe the boundary of each of these Park polygons I can say start editing and I will change my Park polygon to let's say this nice green here and I've selected that for editing and so now I can create a polygon using that construction tool so for example I could in exactly the same way that I'm tracing features for a line I'm doing the same thing for a polygon I decide what my sampling frequency is going to be I'm gonna use a little bit of detail here and you'll notice that if this is called rubber banding is that it's it's showing me that I have to finish a polygon so I'll continue this one in other words I couldn't turn this into a line if I wanted to and I can then if I'm getting close to where I started I want to close the polygon or have it finish at the same place that I started I just right click and say finish sketch and now I have a new polygon feature and there we go if I wanted to trace an existing feature so let's say that I wanted the boundary of my polygon to exactly match the path that I digitized just a line then I can do that as well so if I select my parks to modify and I'm going to save my edits there and so now I'm going to digitize new feature let's see now I take my park and I'm going to select from the toolbar this drop down here you'll notice there's a few different options for editing and if you mouse over them it'll describe which each one is and so in this case for example I mean use the trace tool which is very handy so now when I'm creating my new from polygon what I'll do is I'll select the trace feature and you'll notice that as I get close to an existing feature will snap to the that feature so I'm going to snap or click at the start of that existing path line and then if I drag the cursor along that existing feature it will highlight it and let me know that it's going to actually trace that so I don't actually have to try and click along every single existing vertex and try to get them to be exactly the same I can just trace along and when I get to the end of it I just click and so it automatically creates matching line segments and vertices to the existing line feature so that they're exactly the same which is a really handy thing to be able to to know about and so from then on since I don't have anymore paths I can continue on by tracing if I have to get rid of the trace tool now and just go back to using straight segments and so now I can continue on digitizing the rest of this feature that way and so if I just went around stayed here I'm doing a not great job here and then I'll finish the sketch and so now I have a second feature that's exactly traced along an existing line segment so that's essentially the basics of creating points lines and polygons it's not particularly difficult but in arcmap it's not always that intuitive when you're first starting out so remember to open the create features pane optionally the attribute pane as well and then you can start tracing features using the various construction tools that are available you can change the symbology as you go or do it afterwards there's lots of context menus so essentially if you're right-clicking as you go you can change different options in terms of offsets things like that which you can explore and play with so hopefully that's enough to get you started

Channel: Don Boyes

Views: 132,799

Keywords: arcgis, arcmap, digitize, digitizing, learning gis, how to gis, online, online learning, donboyes

Id: YYwhX-jhthk

Length: 14min 29sec (869 seconds)

Published: Mon Mar 18 2013