3 replies to this topic

[Tarkin]

Dear members of this forum,

In order to use a climatological model (SOLWEIG) for the prediction of mean temperature changes due to vegetation, I need to be able to convert a google earth screenshot of a street into a vector layer (Building edges) in ArcGIS. I'm not sure if there is a method available in ArcGIS to draw lines over the underlying aerial photo> Or maybe there is a tool that converts the outlines of the photograph into lines?

I was hoping if anybody could point me in the right direction. Maybe there are some tutorials available for me to look at? Surprisingly, I did not find any exercise like this in the book Getting started with Arcgis.

Thank you in advance for your help,

Kind Regards.

Tarik

[Matthew Hampton]

Hi Tarkin,

It's difficult to automate that process however there is software available. You would need the ArcScan extension for ArcGIS, but it might not get you what you want quickly or easily. You would be better off digitizing the lines yourself or searching for vector data from a provider. There are many links online to help you learn how to digitize. Here are a few.


http://www.scribd.co...izing-in-ArcGIS
http://www.s4.brown....rles/lab3r3.pdf

[Dustin Edge]

Hi Tarik

The manual process is easy...just create a new shapefile and start editing. But I'm guessing you're after some sort of automated process. You're better off going into a photo editing package first and running a few filters to make the edge lines stand out first. But before you do that, create a world file of your image so you dont lose the georeferencing information.
Once you have a sharper image, a program called WinTopo will help with generating the vectors you need.

One word of caution though, the google licensing clearly states that "scraping" information from their imagery is a big no-no, so you might want to ask such questions in a more generic manner....


Kind Regards

[spg]

As you say street and screenshot I assume it is a small area you're looking at?

If it's UK data, Ordnance Survey have the building outlines available in their MasterMap data, however there are various limitations around using that (not least that you will probably have to pay for it).

Otherwise, as said by Dustin, just create a new feature class and digitise it yourself, possibly with some image modification to make it easier.