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Hot answers tagged spatial-analyst

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What is the "57.29578" that ArcGIS uses in Aspect calculation?

In a GIS aspect is generally shown in radians. 57.29578 is 1 radian in degrees - ArcGIS is using this number when converting to radians. A simple way to remember how to convert from degrees to ...

How get intersection of polygons in the same table by PostGIS?

you can use ST_INTERSECTION using the source table twice. Make sure to avoid comparing the a polygon to itself. Also avoid comparing a pair of polygon twice. SELECT ST_INTERSECTION(a.geom, b.geom), '...
• 42.4k
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COUNT vs. SUM field of zonal statistics as table output table

What you are looking for is COUNT, which is the frequency of the cells that you processed through Zonal Statistics. Sum, on the other hand, is the sum of cell values covered by your polygon. Overly ...
• 4,993

Cube root on ArcGIS raster calculator?

The cube root is to the power of 1/3 so you could use something like: (ras1 * ras2 * ras3) **(1/3) Credit to @JeffreyEvans for correcting the operator for ArcGIS.
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Merge two shapefiles in R

You can use raster::bind. That function combines the geometries and the attributes, even if the variable names do not match. Example data: library(raster) p <- shapefile(system.file("external/lux....
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Finding regions or zones in raster DEM of similar slope or aspect values in ArcGIS for Desktop?

Slope and aspect together tell you about the normal direction to the surface. This is an arrow of unit length pointing straight out from the surface. At a horizontal point it is straight up; along a ...
• 69.9k
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ArcGIS Viewshed Outputs

The error in your approach is that a 2m tall person at Point A who can see a 50m tall structure at Point B does not mean 50m tall person at Point A could see a 2m tall structure at Point B. Here's a ...
• 714
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Understanding aspect units in QGIS

It depends on which of the available aspect calculators you used as QGIS is beter thought of as a 'meta-GIS' rather than a single GIS as it provides a GUI for multiple GIS technologies (e.g. GDAL, ...
• 33.9k
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Merging agricultural rasters using ArcGIS Spatial Analyst?

You can use the Raster Calculator. Something like this should get you what you want: Con("corn.tif" > "wheat.tif", 1, 2) Update for additional question in comments: I would do this in a two ...
• 772

How can i Calculate Road Width in ArcMap?

Possible way to do it is: Create centerlines for your polygons (With Collapse Dual Lines To Centerline after convertion polygons or with Creating Centrelines from Road Polygons/Casings? (not tested) ...
• 862
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Deleting values from raster file using ArcGIS Raster Calculator?

You can use the reclassify tool in Spatial analyst to change your values to NoData (or any other values). You can also use the raster calculator to apply some rules e.g. Con((raster>=20) & (...
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Flow Direction created from depressionless DEM inaccurate in flat areas

These are common problems, typically resolved by stream burning, but that relies on you having a vector network to enforce drainage. I recommend you check out the free GIS software Whitebox GAT it has ...
• 43.9k
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ArcPy map algebra equivalent for "any"?

You could sum the rasters and test whether the total is greater than 0. list_of_rasters = [Raster(a), Raster(b), Raster(c)] z = CellStatistics(list_of_rasters, "SUM") > 0
• 67.4k
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Convert polygon to line using ArcGIS Desktop?

I'm not sure which license level you have access to, but if you're working with an Advanced license for ArcGIS Desktop, you can use the "Collapse dual lines to Center line" tool (tool description here)...
• 1,302
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Clustering neighboring points inside ArcGIS Desktop?

Result of clustering technique suggested by @Albert shown by colours of points in the picture below. Output will greatly depend on physical order of points in a feature class. At some stage it will ...
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Interpolation with 10 data points

Both methods are "appropriate". IDW basically says "half way between a point valued 6 and a point valued 8 the value is going to be 7", but extended to the distance to multiple ...
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Enabling ArcGIS Spatial Analyst extension by default?

From Esri Support http://communityhub.esriuk.com/technicalsupport/2014/3/23/silently-enable-extensions-for-arcgis-for-desktop-10x.html It is possible to activate extensions silently during ...
• 164

Calculating percentage distribution for field in each polygon in ArcGIS Desktop?

You can use the tabulate area tool in ArcGIS spatial analyst. It will give your the frequency of each raster value inside each polygon, which you can convert to percentage afterwards. Just make sure ...
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Calculate NDVI using ArcPy Spatial Analyst

I presume you're using ArcGIS Desktop which uses python 2x, not ArcGIS Pro which uses python 3x. Side note: this is one example of why it's important to specify the software you are using. In python ...
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Some zones disappear when running Zonal Statistics as Table in ArcGIS

The Zonal Statistics as Table documentation states the following: If the areas of single features are similar to or smaller than the area of single cells in the value raster, in the feature-to-...
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Counting raster values in each polygon using ArcGIS Desktop?

If the smaller watersheds are in the same shapefile as the larger watershed, select and save the smaller watersheds as a separate shapefile. Run the Zonal Statisticstool with Variety as the target ...
• 904
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Counting raster values in each polygon using ArcGIS Desktop?

One of the powerful tools in ArcGIS is the Tabulate Area tool, which allows you to calculate the area of each land use within each polygon in the polygon shapefile (watershed in your case). The ...
• 41.2k

Creating Extent of Data within Raster (not just boundary of raster) in ArcGIS Desktop?

One approach is to reclassify all cells that have a value to 1 and the leave nodata as nodata, so you end up with a binary raster of 1 or nodata. Then use the raster to polygon tool to convert it to a ...
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Creating glacier centerline in ArcMap?

This is workflow for single glacier: arcpy.PolygonToLine_management("Glacier", "./OUTLINE.shp") arcpy.InterpolateShape_3d("DEM", "OUTLINE", "./outline3d.shp") arcpy.FeatureVerticesToPoints_management(...
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ArcPy Raster Calculator error " 'str' object has no attribute 'save' "

Per the Esri documentation, this tool is not available in arcpy scripting: http://desktop.arcgis.com/en/arcmap/latest/tools/spatial-analyst-toolbox/raster-calculator.htm Note: The Raster ...
• 3,706
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Using ArcGIS to extend a polygon in one direction up to the edge of another polygon

For the simplest approach with zero coding I think @FelixIP has nailed it! Simply use the Euclidean Allocation tool, making sure you set your outer boundary as the mask and processing extent, then ...
• 43.9k
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Is there a setting to force ignore invalid geometries when performing spatial analysis in QGIS 3.0?

In QGIS 3, go to Settings tab, Options, navigate to Processing and expand the General settings. For "Invalid features filtering" select "Do not filter (better performance)" from the corresponding ...
• 530
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Is there a limit to the number of raster layers in Raster Calculator?

You can use Cell Statistics instead of raster calculator to get the average. I do not expect there is a limit to the number of raster to be used, but adding 244 is also too much in raster calculator. ...
• 41.2k
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Zonal Statistics is returning null values in ArcGIS Desktop?

You could try resampling the raster to a finer resolution. Not sure why this works but accourding to the help section for version 10.3 (not present in 10.6): If the zone input is a feature dataset ...
• 75.3k