A GIS question: I want to summarize the percent of each pixel type in a raster layer (it's a land use/ land cover layer) in a circle around each point in a point shapefile. There are hundreds of points so I don't want to do this manually for each point. I use ArcGIS 10.x and can't seem to figure it out. Anyone have experience with this? Thanks!
@Leif,
If I got your question well !
- Convert raster to polygon
- Create a buffer around your points (with a width less than pixel size)
- Clip your polygon layer with buffered layer
- Export the attribute of the clipped feature using "XTools" to a .xls file
- The percent of each Luse type can be calculated using excel
Hi Leif,
you should try the tool called Zonal Statistics as Table, I guess that it would fit to your needs. The inputs are your raster and zones, i.e. buffers around points with unique ID.
Regards
Dear Leif L. Richardson,
Referred to your question, I think the following process can solve your problems:
1. Reclassify the each type, you can check the table and confirm the pixels in each land type.
2. Using the circle to overlay the reclassify layer, you will get the circle covering the numbers of pixels.
Hope it helps.
Regards,
Dou
Alternatively you can create a buffer around points, extract the land cover raster by this mask and convert the result to polygons.
Regards, Giovanni
You "... want to summarize the percent of each pixel type..." of your land cover map. Therefore, first recode the land cover into a binary map (1/0) for each land cover type of interest. Second, calculate the mean value around each pixel with the "Focal Statistics" tool inside Spatial Analysts Neighborhood toolbox. Third, extract the values from these new neighborhood rasters with "Extract Multi Values To Points" tool inside the Extraction toolbox.
1- create a polygon layer for the points with radius identified.
2- Convert the raster land use map into points.
3- in the TOC in ArcGIS click on the polygon map (buffer zone) and use the join and relate from the right hand click menu and select join.
4- change the first option to be "join data from another layer based on spatial location.
5- Identify the point layer of land use.
6- select the method of attribute summarization (function), minimum, max, mean. this will add an attribute to the attribute table with the land use type.
We used this method to assign soil property for each soil mapping unit using point data inside each unit.
Thank you all for your help with this. I did buffer those points, but then had many that overlapped, making use of some of these approaches impossible. ESRI has apparently heard about this from others, so there is a tool in the Spatial Analyst Supplemental Tools (V. 1.3) that can handle this: 'Tabulate Area 2'.
Hi Leif,
As Lukas pointed out, check the Zonal statistics as table (http://desktop.arcgis.com/en/arcmap/10.3/tools/spatial-analyst-toolbox/zonal-statistics-as-table.htm). You can make a buffer around points on the appropriate distance and use this buffer as the input zone. For the zone field use the id of each point for. The inValue raster should be your land cover data in raster format. The output is a table summarising most common statistics (min, max, range, mean, std, sum, variety, majority, minortiy and median) per each land cover type in your input zone. But you are really interested on the area of each land cover in your buffer zone, so you can just select one of them and ignore it afterwards.
Hope this helps,
Raquel
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