erase tool while heads up digitizing

[JeremyOlynik1]

Hello,

I'm wondering if anyone knows of a third party tool or something built into ArcGIS 10x that will erase or clip an area of a polygon quickly and efficiently. I'm thinking something like the 'magic eraser tool' in Photoshop. I'm trying to manually digitize sand within reef communities and as it stands I'm digitizing a polygon over-top of the  the wider 'reef' polygon and then clipping the underlying data... all the while thinking that there has to be a better way of doing it as there are many areas. These are areas where image classification isn't working out well.

Any thoughts are appreciated thank you.

[MitchHolley1]

Have you tried the Erase (Anaylsis) tool ArcGIS Help 10.1- Erase

It's in the  'Analysis Tools' -->'Overlay' toolbox

[JeremyOlynik1]

Thanks for the reply Mitch.  I don't have the two layers separated as yet but if I did then I would use the erase tool for that for sure.  Here is an example of what I'm trying to separate.

[ChrisSmith7]

Not sure if this helps you at all, but check out the polygon editing tools of ET Geo Tools:

The concept of Polygon editing

ET GeoTools User Guide

There are some tools that will make your polygon editing work flow a bit easier...

[JeremyOlynik1]

Thanks Chris. It looks like the polygon editing tool isn't available in the free version of ET GeoTools. Also, I tried using it and it looks like there is no 'streaming vertices' available when editing so it would be difficult to digitize multiple polygons. I do use ET GeoWizards often and can recommend that as well for geoprocessing.

[KyleBalke__GISP]

Jeremy,

Not sure exactly if it fits your need but ArcMap does have the ability to do an interactive clip while editing. 

• Start your editing session
• Select the features you want to clip out of your polygon
• Slick the Editor button on the Edit tool bar
• Select Clip from the list
• Choose Discard the area that intersects on the Clip dialog

And then the result

[JeremyOlynik1]

Thanks Kyle - yeah, that's what I've been doing thus far.  I'm creating a new polygon using streaming vertices and then using the clip function on the editor toolbar.  It does work although I was hoping to avoid the need to 'clip' the background polygon somehow to speed up the process. If there was some kind of 'eraser' of the background polygon using a brush of a certain width, I think that would be ideal.  It is possible that it just doesn't exist!

[KyleBalke__GISP]

It doesn't exist (as far as I know) if you are working with vector data...just goes against the structure of the data model.  There is a Raster Painting option in ArcMap that you might take a look at and see if you can use it in conjunction with the output of an image classification. 

I feel your pain...I have digitized large forested areas for several custom maps I have created in the past.

[JeremyOlynik1]

Yeah, that makes sense.  I think even if there was a script tied to a new polygon where it took priority over everything behind it and automatically clipped the underlying polygon.  This way I wouldn't have to select clip every time.

[MitchHolley1]

Jeremy,

Try using the 'Extract by Mask' (Spatial Analyst) tool.  ArcGIS Help 10.1- Extract by Mask

If that red line is a feature class.  This tool will work perfectly