5 replies to this topic

[snobblepopkin]

I'm a novice ArcMap user and was hoping someone could point me in the right direction. I want to trace this aerial photo I have and turn it into a map. I downloaded the MrSID image I want from the US Government, but I can't figure out how to "edit" it in ArcMap. I want to create a shapefile that I can export into Illustrator.

If I drag the raster dataset into ArcMap and the image appears fine, but "Start Editing" in the edit toolbar is grayed out and unavailable. Am I supposed to be using the ArcScan extension? How do I go about tracing a MrSID image / raster dataset?

Any help is greatly appreciated.

[frax]

You need to create a new feature class/shapefile that you can edit first - all your edits will land in this object. Check out the toolbox and the help file for creating a new layer.

[SaultDon]

There are also some good tutorials from ESRI's help: Editing Tutorial

This is editing specifically in ArcGIS 10, but I am sure similar tutorials can be found for the other help versions: 9.3 Editing Tutorial (PDF)

The editing environment has been re-vamped in V10 with noticeable changes to the snapping environment (it has become more intuitive, AutoCAD style)

[Gretchen Peterson]

Yes, create a new shapefile or geodatabase in ArcCatalog, add it to your ArcMap project, then go to the editor toolbar and click start editing to start editing the new shapefile. You'll need to create a new shapefile/geodatabase for the lines you want to draw, another for the areas you want to delineate, and another for any points you'll be capturing. Once you have clicked Start Editing you use the edit tools to "trace" what you see on the map. Be sure to save as you go along.

[SaultDon]

d Start Editing you use the edit tools to "trace" what you see on the map.

To avoid any confusion, Trace is an editing function inside ArcGIS.

Trace is a tool that will allow you to create/modify a feature based on existing features.
The feature(s) that will be traced/followed must be selected in order to be included in the trace (don't need to select the feature being edited) where multiple layers can be selected for the trace like roads and rivers, contour lines, etc...

ie, modifying a boundary to run along a rivers edge/centreline where in this case, the river (which is being traced) would be the feature to select with the select tool)


If you have access to ArcScan, you can use the Vectorization Trace tool which is raster based where it can identify contiguous surfaces in a raster without setting up any raster snapping.

[snobblepopkin]

Thanks everyone for your replies, this was all very helpful information.