Tag Info

New answers tagged

0

To clarify, say, there is a raster and with random values 1-10. I want to input this raster and return a new raster that is all no data except for where the original raster = 5 I use numpy.where for that. Something like: numpy.where ( [condition], [if TRUE do this], [if FALSE do this] ) outarray = numpy.where((outarray==5),5 , 9999) ...


0

Take a look at terrain datasets inside a file geodatabase if you also have your LiDAR in vector format. Otherwise I think you will find Mosaic Datasets useful. That allows you to combine multiple DEMs or other image types on the fly and allow you to apply functions on the fly to create hillshades or slope rasters, etc. ArcGIS help has a very good section on ...


3

If your bathymetric data are current in the form of survey points then you should interpolate them onto a raster grid of the same resolution and extent as your LiDAR data. There are several methods for interpolating these points available in ArcGIS such as splining, IDW and kriging. The most appropriate method to use will depend on your data characteristics ...


1

you could automate this with a loop in Python. Arcpy uses "lazy computing, so this will be evaluated when you save. import arcpy from arcpy.sa import * imList = glob.glob("your_path/*.jpg") outraster = raster(imList[0]) i=0 for im in imList: if i>0: outraster += raster(im) i+=1 outraster.save("outputname")


5

It seems that the arcpy syntax can be used directly in raster calculator. Therefore the properties of this page can be used. For instance Con("raster" > "raster".mean, 1, 0) works. Other examples : minimum, maximum, mean, meanCellHeight, meanCellWidth, extent.XMin, extent.YMax, etc


0

You should use globle mapper for resampling , this is very helpful. Also You can use arcgis, try simply export data . during this change cell size. Then you will find the same pixel value of both raster images.


0

You need to stretch the NDVI floating point values (-1 to 1) to 8-bit unsigned (0 - 255). If you convert the float to integer directly, the resulting raster will have only one integer value. You can stretch the values in the Raster Calculator using the following equation: (NDVI - -1) * 255 / (1 - -1) + 0


0

KrigingModelOrdinary is another function in the arcpy.sa module. If you want to use it as a variable, it needs to be defined earlier in your code. The Arc help page walks through the necessary inputs/usage; the following is a snippet based on their example. # Create KrigingModelOrdinary Object lagSize = 70000 majorRange = 250000 partialSill = 180000 nugget ...


2

Menno's answer will work but it will work but it will always round down. For example, 99.99999 becomes 99. This function in the raster calculator or map algebra tool will do logical rounding. Int(yourraster + 0.5). This way 99.99999 becomes 100 and and 99.49999 becomes 99.


2

From the fact that you plan to use focal statistics I infer that you must be able to use the spatial analyst extension. In the spatial analyst toolbox there is a tool Int in the Math toolset which converts a floating point raster to an integer raster.


1

Straightforward no, but a not too hard block of Python code might help you out. First, make sure you have added a new field in the Red Polygon attribute table and call it something like "field_count". The code is this: uc = arcpy.UpdateCursor(redPolys) yellowLyr = arcpy.MakeFeatureLayer_management(yellowPolys) for row in uc: geometry = ...


3

I was curious so I did a small test to see if the two programs perform the same function. The quick answer is yes and no. Let's have a look- Random set of 100 points with a random weight value: Setup KDE in ArcMap 10.2.1: Setup KDE in qGIS 2.0.1: Compare the results. I adjusted the symbology so that the discrete values were equal interval, 6 ...


3

Pick is the map algebra analog of a "case" or "switch" statement. Like them it is not indispensable but it can be convenient (and more efficient than deeply nested binary logical operators). Notable among the uses to which I have put this operation is its ability to implement a cellular automaton. Another handy use is random selection of rasters. A ...


4

most of the tool can be replaced with Map algebra, but the syntax of pick makes it easy to use. I've used it for mosaicking with multiple masks (you have a set of classification, and you want to combine them based on geographical stratification.) It is also quite usefull in combination of the local toolset. For example, one of those tools can find the ...


0

it´s seems you have digital numbers, if you want to transform it to reflectance read this article. For atmospheric correction you can use dark subtraction or Flaash (not in ArcGis). I think that ArcGis is not the best software for atmospheric correction. If you are doing a temporal analysis you must perform an atmospheric correction.


3

For building complex statements, you can get more information here It is important to know the precedence level of the operators. For example, Boolean (~, &, ^,|) operators have a higher precedence level than Relational (<, <=, >, >=, ==, !=) operators, which has an impact on how you construct your expressions. For more information on ...


1

I've just spent ages on this, so to spare everyone else the trouble here's the cheat sheet: It appears you need to surround each individual comparison in brackets, and use the | symbol as the "or": Con(("Raster1" > 10) | ("Raster2" < 20),30) (Please edit this answer, and post a link to the documentation which mentions this, if it exists)


0

This tool might be of benefit to you if you want to convert your rasters to vector. There is a OWA function and a WLC(weighted linear combination) there appears to be support for ArcGIS 10.1 and above. http://mcda4arcmap.codeplex.com/ and a paper http://www.ryerson.ca/~crinner/pubs/Pages12-13_from_Cartouche86_Winter-Spring2013.pdf


0

In my education in GIS, I met some statistical methods, however I never encountered better, than AHP for weighting objectively. Unfortunately, there was only one software which provided built-in AHP support (surprisingly an entire wizard) for this purpose: IDRISI. There are some user scripts for ArcGIS, like AHP 1.1 or AHP-OWA 2.0, which has Ordered weighted ...


0

Not entirely sure what you are after experimentally but you may want to investigate a Weights of Evidence approach.



Top 50 recent answers are included