Generally we apply GIS for generating a clear geographical image of an area which includes vegetation/forest, snow cover, land etc. I want to know whether we can use google maps for this? If yes, how?
From the context of your question I am guessing that you want to draw clear lines of delimitation between land use / land cover categories. Before attempting to answer, let's look at the manual method for this -- you have a printed map, and you prepare "polygons" or lines marking the different sub areas. You digitize the boundaries on a nice big flat mapping table. (Basically like clicking a mouse-like puck on the edges.) The same idea applies to a geographic image -- you have to know where / what lines you want (with all the challenges of fuzzy transitions) AND you have to get the system to automate the edge detection of the regions. I assume you don't want to digitize the boundaries by hand! So, one way might be to rasterize (grid cell) the map, and define some properties of the cells that you know are associated with various land categories. The best idea is to imagine what process you would have to use as a human interpreter and then find the analogous steps in air photo interpretation or image classification software. ERDAS Imagine is a very capable product in this area.Training or classification involves some science and some art!
I hope I have not misunderstood your question.
From the context of your question I am guessing that you want to draw clear lines of delimitation between land use / land cover categories. Before attempting to answer, let's look at the manual method for this -- you have a printed map, and you prepare "polygons" or lines marking the different sub areas. You digitize the boundaries on a nice big flat mapping table. (Basically like clicking a mouse-like puck on the edges.) The same idea applies to a geographic image -- you have to know where / what lines you want (with all the challenges of fuzzy transitions) AND you have to get the system to automate the edge detection of the regions. I assume you don't want to digitize the boundaries by hand! So, one way might be to rasterize (grid cell) the map, and define some properties of the cells that you know are associated with various land categories. The best idea is to imagine what process you would have to use as a human interpreter and then find the analogous steps in air photo interpretation or image classification software. ERDAS Imagine is a very capable product in this area.Training or classification involves some science and some art!
I hope I have not misunderstood your question.
Dear Saveena, you may find a brand new tool developed at FAO of use in the display and analysis of landsat imagery via google earth: try teh toll "Connect Earth" at teh following link: http://www.openforis.org/tools/collect-earth.html
Best Regards,
Francesco
Dear Saveena
Once I followed a technique that you may use in yours. I collected a shapefile (.shp) for the specified region, converted the file to a .kmz file, opened google earth and upload that .kmz file. It specifies the area of interest (aoi) with yellow borders. Saving such files as a .jpg file may serve your purpose.
Siddiq
Saveena,
If you are using google for updated aerial photography (because they always seem to have the newest available images), you can take a "clipping" of the map (using the windows 'snipping tool') shown in google maps, save it as a .jpeg, and then "georeference" the image in your GIS.
If you are using ArcGIS there is a toolbar for georeferencing images.
Hope this helps.
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