mtsini Posted May 4, 2011 Report Share Posted May 4, 2011 Hi Everyone. I hope somebody can help me please. I am trying to create a vegetation vector data layer by extracting the data from 50K raster mapping or colour imagery. Because of the large amounts of vegetated areas within my AO I don't want to have to mandrolically digitise. So far my thoughts have been. Convert 50k Raster mapping vector in arc toolbox. This assigns a value to all the feature of the map that have now been vectorised from this I can work out the value that has been assigned to all the vegetated areas and create a seperate feature from this. However my problem is that when you turn the raster into vector it draws a boundary around any map symbology or lettering that was also on the map face. Is there anyway to "clean" this so that I am only left with the vegetated area complete as a polygon? A collegue mentioned that I could use the imagery to use the NVDI to extract the data another way, using Erdas. Having not done this before, does anyone have experience doing feature extraction this way? Any help or suggestions would be greatly appreciated Many thanks Quote Link to comment Share on other sites More sharing options...
3dbu Posted May 4, 2011 Report Share Posted May 4, 2011 collegue if you have the imagery of this site you can make a classification , or using the NDVI if dont have idea how work this i can help to you, but first tell us the type of imagery that have ...this can be a usefull for you....but if no hava the imagery of this site you need to seek in the web and try to download for make this classification.... regards. Quote Link to comment Share on other sites More sharing options...
Lurker Posted May 5, 2011 Report Share Posted May 5, 2011 NDVI will work by using IR canal, all vegetation will turn to RED regards, Quote Link to comment Share on other sites More sharing options...
mtsini Posted May 9, 2011 Author Report Share Posted May 9, 2011 Thanks 3dbu and Lurker, been away for the last few days so sorry that i haven't replied. I do not have any multispectral imagery available so it looks like I will need to try and extract the feature data using the pixel values of the raster mapping. The only imagery i have is orthorectified images which won't be ideal but there I am only looking for a generalisation of the area. Does anyone know of any sources of free landsat 7 imagery or other MSI suitable for Terrrain Catergorisation for Spain, particularly the Soria district? 3dbu if have time would you mind putting a quick guide of how to use the NVDI to extract the info via classification. Its been a number of years since i last did one! I am using ERDAS imagine 9.3 but have access to 2011 if needed. Cheers for all your help. Quote Link to comment Share on other sites More sharing options...
Lurker Posted May 9, 2011 Report Share Posted May 9, 2011 landsat can be download from here : http://www.glcf.umd.edu/data/landsat/ Quote Link to comment Share on other sites More sharing options...
3dbu Posted May 9, 2011 Report Share Posted May 9, 2011 this is part of capacitation that i did for gubernamental agency in my country ,about Remote Sensing and GIS , there you get step by step how to use the NDVI in arcGIS and the method for make this analyst...i hope be usefull for you if have doubt please tellme and i gonna make a video for explain bether. http://www.megaupload.com/?d=WKFNO9KF regards. 3dbu Quote Link to comment Share on other sites More sharing options...
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