ArcGIS Notes (for ArcMap10)

How to create shape file from x y coordinates in ArcGIS 10 and download environmental data for those points

-        Arctoolbox --> Data Management Tools --> Layers and Table Views --> Make XY Event Layer

-        Load in a csv file with x and y data (can have other descriptors as well).  If using lati and longi, longi is x and lati is y.

-        Make sure to set the spatial reference to the same spatial reference as the other shapefiles you will be extracting data from (e.g., Albers Equal Conical Area)

-        This will create point data as a shape file

-        Download WorldClim variables (or whatever variables you’re interested in)

-        Connect to folder with WorldClim variables

-        Drag each variable’s shape file into the map at a time

-        Spatial Analyst Tools --> Extraction --> Extract Values to Points

-        Add in the points shape file as Input point features, and use the environmental data as Input Raster

-        Check the box to at the bottom “Append all the input raster attributes to the output point features”

-        Open attribute table of new layer that you’ve created

-        Click “Export” from the attribute table options

-        Save as a .txt file

-        Open the .txt file in Excel and it will be comma delimited

-        Save the txt file as an excel file

How to append land cover data to x y coordinate point files in ArcGIS 10

-        Download a land cover shapefile (a list of websites with land cover data for download can be found at the USGS site http://landcover.usgs.gov/landcoverdata.php)

-        Add the land cover shape file to your ArcGIS session (just drag the file from your folder connections under “Catalog”)

-        Create a layer with your x y geographic coordinates making sure the projection matches the projection of the land cover data (use Arctoolbox à Data Management Tools à Layers and Table Views à Make XY Event, and specify the projection; x y coordinates need a world projection, and then match the land cover data to that projection)

-        The land cover data are usually represented by a categorical variable.  Only continuous variables can be extracted to a layer of points (as far as I can tell), so you’ll have to subset the land cover data.

-        To subset use Spatial Analyst Tools --> Extraction --> Extract by Attributes.  Add your land cover layer as the “Input Raster”, in the “Where Clause” select just one of the categories of land cover (e.g., “Class_name” = “Mixed Forest”) and name your “Output Raster” appropriately.

-        Now you have created a new layer with just one land cover variable.   Now use Spatial Analyst Tools --> Extraction --> Extract Values to Points and make the “Input Point Features” your x y coordinate layer and the “Input Raster” the newly created land cover layer of just one category.

-        Select “Append all the input raster attributes…” in the same box before pressing OK

-        Your x y coordinate layer will now have a column in the “Attribute Table” (accessed by right-clicking the layer and selecting “Open Attribute Table”) for the land cover category you selected.  The new column will include only two numbers, -9999 and some positive integer.  The -9999 means your point does not overlap with specified land cover category and the positive integer means it does.

-        Click “Export” from the attribute table options

-        Save as a .txt file

-        Open the .txt file in Excel and it will be comma delimited

Save the .txt file as an excel file
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