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Wow! What a relief to have your experience and creative problem solving in such a short time. THANK YOU! I will try both options as suggested. Which brings me to another issue. Essentially, this analysis is a 7-year time series; each year(.mxd) has a unique shiptrack of data with lat/lon points (and the main research data) to be compared to the corresponding values on the daily satellite products for the dates covered in the cruise. The length is usually around 40-90days, from each I have already extracted raster cell values I needed. So, my concern is, can each map's folder of satellite layers be converted efficiently, in batches? I don't have much experience with that process, and the last time I tried (years ago) it kept crashing arc. I think that was because the images are hemispheric (polar). It would be nice to keep them at that scale because I will need to do the same distance query for other cruises in other sub-regions. You've made my day!
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02-04-2014
04:32 PM
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Hello~ I have posted a similar thread in the Python forum. Surprisingly, it has received over 100 views, but sadly, no replies! I need to find the distance from each point in a shapefile to the nearest raster cell with a specific value. The shapefile is a time series, so for each date, there might be one or more points. I have all the rasters per date of the points in the shapefile. So for each date, I need to link the data points from the shapefile to the corresponding raster of the same date and calculate the distance from each point to the raster cell value of a specific value (< = 15). Is there a tool or python code to accomplish this? Thank you, A.O.
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02-03-2014
07:39 PM
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Hello again~ Thanks for your quick replies. I did try to apply the script you provided after combining both of your suggestions and got some runtime errors, a few that were typos, but the final claimed the field is not nullable (my Lon_M field). I have a IT order in and hope someone will update my license to 10.2 so I can work directly with the Add Geometry Attributes tool! If I don't get the update in the next few days, I might have to ask for more specific direction. Cheers, Alice
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01-07-2014
04:58 PM
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Hello I have points with XY coordinates in GCS84 and need to convert them to meters before extracting raster cell values from the points. I know I can do this with the Calculate Geometry window from the drop-down menu off the field name in the attribute table, but I'd like to add this step into a longer python code after adding the new field. Should be easy, right? The Calculate Geometry window asks for the following input (I've entered mine): Property: Y Coordinate of Point Coordinate System: Use coordinate system of the data frame (PCS:Polar Stereographic) Units: Meters Thanks in advance for any ideas or help! ~Alice
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01-06-2014
08:13 PM
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Ipinner~ Thank you for your response. I think I communicated my issue poorly. The result I'm looking for is the raster value of the buffered point. So if my lat/lon point fell into a cell with a value of 25, but after a 1nm or 1852m buffer, it crossed about half of its area in the buffer into a cell with a value of 75, I'd hope to get a weighted average of the 2 cells which the buffered zone covered, expecting a result around 50 (realizing that before the buffer, the point confidently fell within the cell with a value of 25 and then had a near equal amount cover the cell with a value of 75). The Focal Stats tool is averaging the raster's cells within the buffer distance to the original raster cell values. I need the lat/lon point to represent a 1nm radius of the exact lat/lon. When the point is buffered, it becomes a polygon. Is there a way to extract the raster cell values, averaged if necessary, which a polygon covers? Thanks again, Alice
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01-06-2014
04:23 PM
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Hello, I have a raster of 25km2 and point features with lat/lon. I have successfully extracted all raster values with the points in the lat/lon data set from the raster, but then wanted the points to be buffered by 1nmi, I can't seem to find a way to have the buffered area extract the raster values. What I want is to be able to so is get the average (weighted?) for the raster value when a buffered point overlaps one or more raster pixels. Is this possible? Thank you for any clues or direction! And Happy Thanksgiving to ALL~ ~Alice
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11-28-2013
01:30 PM
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Xander, Thank you for the quick response. What you wrote made sense, but I have unsatisfactory results. The output in the column is 110 for each point in my Shapefile Feature Class (which just happens to be the value of the pixels at the North Pole (90N, all E/W)). This is confusing because both layers are visualized on the map correctly and when I use the Info tool to id the values for a point over a pixel, it returns the correct values for both. Yes, my raster is in North Polar Sterographic projection, with meters as linear units and degree as angular units. My Point Shapefile Properties lists GCS_WGS_1984 as the Geographic Coordinate System. In ArcMap, the Data Frame properties lists the coordinate system as Polar Stereographic with a Stereographic North Pole projection, and "GCS_ WGS_1984 and Datum: D_WGS_1984" listed as well. I've dropped a copy of the Shapefile in with a Projected Coordinate System of North Polar Sterographic for kicks, and that is visualized at the North Pole. Is the problem that I can't sync Projected and Geographic Coordinate systems? Again, any insight and direction that you can provide is most appreciated! Cheers, Alice
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10-10-2013
04:06 PM
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Hello~ I have a shapefile with lat/lons in decimal degrees which I want to use to extract the raster cell value, which is in meters. How can I convert the decimal degrees to meters, which is the geographical location of each raster cell? If I use the Info tool to query a point from the shapefile over the raster, Arc easily pulls the shapefile point and raster cell values. I want to be able to do this in arcpy and sync this raster cell value onto my attribute table. My shapefile is a time series of 45 days and I have daily rasters. I want to query each point to the corresponding raster to extract the appropriate cell value for the date and lat/lon of each point. Any help is appreciated! Thanks.
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10-08-2013
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