Tagged Questions

2
votes
2answers
31 views

Solar analysis; Are there any issues with splitting large DEM

I am trying to run Solar analysis in ArcGIS and it is an enormous DEM of a very mountainous region. I'm obviously going to have to split the DEM, but I was wondering if there are any issues with ...
0
votes
1answer
34 views

territory analysis

I want to determine the territories in which customers to a bank has the shortest path. It can be done with desktop software packages or programming if it is needed. Does anybody has idea on how to ...
0
votes
0answers
34 views

How specify a corridor minwidth?

I’m trying to make a corridor between two substations with ArcGIS, a macro corridor and a micro corridor. I have two questions in this respect and would be grateful for your suggestions. a) How can ...
2
votes
1answer
64 views

About regression analysis in arcgis

I'm trying to do regression analysis using a shapefile which contains dependent variable (NDVI) and explanatory variable (prec) in Arcgis. First, I run GWR analysis and then run spatial ...
0
votes
1answer
48 views

Elevation Drop Along a Stream [duplicate]

Previous discussion In reference to a previous discussion, suppose I want to cut the stream every 100 m and find the elevation drop every 100 m. How can I do this?
1
vote
2answers
109 views

“Extract by Mask” changing raster pixel values…or not?

I am using ArcMap 10.0 and am confused by my Extract by Mask output rasters. I hope to eliminate the black background from three Landsat ER Mapper images so that I can mosaic them. Originally I ...
1
vote
2answers
49 views

How can i use field of view in ArcGIS?

The field of view analysis in GIS is a polygon file that shows the portions of an area that are visible versus no visible across a terrain starting from a given point. see this Link How can I use ...
1
vote
0answers
43 views

Plotting time-series data in ArcGIS

I'm attempting to produce interpolated plots of water quality time-series data from ArcSDE. This is the data format: OID WELL_ID WELL_NAME SAMPLE_ID SAMPLE_DAT PARAM RESULT ...
4
votes
1answer
95 views

Raster Reclassify fails upon Completion in ArcGIS

When attempting to reclassify a raster in a student edition of ArcInfo 10, the program crashes without an error upon reaching 100%. The reclassified raster is written, but with no spatial info. I've ...
5
votes
1answer
259 views

How to calculate the flood volume using a LiDAR DEM and a HEC-RAS floodplain polygon

I’ve got a vexing GIS analysis problem which is conceptually fairly straightforward, but in reality more challenging to figure out…. Basically, I need to calculate the VOLUME of floodwater within a ...
7
votes
1answer
136 views

Calculating distance from points to different class in raster

I am looking for some advice on how to calculate the distance from a point to a different class of a raster. Specifically, I have observations (points) of animal use overlaid on land cover data. For ...
9
votes
2answers
334 views

How can I get weighted Flow Accumulation to deal with negative values? [duplicate]

here's one I haven't seen anywhere, to my surprise. I am trying to do something a little different with Flow Accumulation, which I would think has been attempted before, but it's stumping me for now. ...
2
votes
4answers
117 views

Error When Trying to Run Slope Analysis Script

I have written a script which is supposed to loop through all the rasters in a folder and perform a slope analysis on each raster and save the results in another folder. I keep getting the following ...
-2
votes
1answer
95 views

How to calculate cumulative mean in Arcgis

I'd like to get cumulative mean value from a multiband image (4 bands). How can I do it in Arcgis, ERDAS and ENVI? Thanks in advance
1
vote
0answers
97 views

About zonal statistic function in ARCGIS

I calculated zonal statistic in Arcgis to get max/min value of each LC types. Broadly, LC image include forest, grassland, waterbody etc. But output max value of zonal statistic function give me 0.972 ...
1
vote
1answer
69 views

How can I multiply each band of multiband image by separate scalars?

I have an image with 5 bands. I need to multiply each band of this image by different scalars one time (I'm lazy to do it one by one) and then get multiband image as a output. For example ...
5
votes
3answers
298 views

Extract Overlapping Polygon Data to Points

I have a polygon data set of corn yield collected by a combine. However, as the combine drove through the field, there was slight overlap between passes, leading to overlapping polygons within the ...
0
votes
2answers
340 views

Difference between Geostatistical analysis and Spatial analysis tool for interpolation

I did interpolation on point data using "Geostatistical Analyst" tool. It gives me surface layer. Then I exported this layer into raster image (by right click on this layer=>export data into raster) ...
3
votes
2answers
570 views

Extract raster by mask output does not completely overlap the mask

I have a flow accumulation grid and a shapefile containing catchment areas. Now I want to do some calculations on them so I need to extract data from cells in the raster adjacent to certain catchment ...
3
votes
2answers
303 views

How to find out the Stream Order from DEM

I have DEM Data for the study area, I want to know how to find out the stream order using DEM. I saw Stream order tool in Hydrology toolset in ArcGIS. in Stream order tool what is input stream raster ...
1
vote
1answer
138 views

GWR Result Issues

I am working with GWR to identify if there are any relationships between 'extreme' events and disease incidence. The use of GWR has been employed because I am working in a region where local ...
6
votes
1answer
180 views

Why does tool take longer to run when in Python script?

I have written a python script that does some euclidean allocation. For that I use arcpy.gp.EucAllocation_sa() method. Now, my python script takes 30-40% extra time than spatial analyst euclidean ...
14
votes
5answers
2k views

Ways to Speed Up Python Scripts Running As ArcGIS Tools

This is a pretty general question. I just wondering what tips and tricks GIS programmers have used to speed up arcpy scripts that you import into the toolbox and run. I work most everyday writing ...
2
votes
2answers
149 views

Why would a perfectly usable raster mosaic produce an unusable clipped raster?

I'm getting funky results from Extract By Mask (spatial analyst). I'm clipping a Raster Mosaic of DEMs from the National Elevation Dataset with polygons. I have a script to run through 15 separate ...
4
votes
2answers
531 views

Does a Zonal Statistics value change when applied on a subset of data?

I have generated zonal statistics using feature zone data on a value raster. This shapefile contains about 20000 polygons and the analysis went without a hitch. While testing quality, I ran the same ...
3
votes
1answer
185 views

Estimating cline width at multiple points along a trait gradient

In the map below I have 66 (green) points along the midpoint (0.5) for an allele frequency cline across the region (see map). I created the points by placing a point every 25 km along the 0.5 allele ...
4
votes
1answer
617 views

How should I correctly exaggerate a hillshade raster (ArcGIS10, Spatial Analyst)?

I once wanted to generalize a high resolution raster and instead of MEAN i accidentally selected the default SUM technique, using a cell factor 5 (Lidar DEM is 1m resolution). When I used this result ...
2
votes
2answers
145 views

Spatial analysis? Two layers?

One is LandPlot and the other is Soils. When I open the LandPlot attribute table I see I have 500 specific plots of land. When I open the Soils attribute table I see I have 5 types of soils (let's ...
3
votes
2answers
109 views

How to find the distance within which a set percentage of features fall?

Someone asked a question earlier about finding the number of features within a certain distance of another feature in ArcView. I have the opposite question: is there any way, in ArcGIS 10, to find the ...
2
votes
0answers
313 views

How to calculate Solar Radiation falling on vertical surfaces using DEMs and ArcGIS?

I am using ArcGIS10 Area Solar Radiation tool to calculate irradiation on horizontal surfaces (building roofs) but need to do the same for vertical surfaces (building facades). Any ideas on how to do ...
1
vote
1answer
231 views

How to use (make sense of) results from ArcGIS Area Solar Radiation tool?

I am using the tool Area Solar Radiation in ArcMap10 to analyse DEMs of parts of a city (area equivalent to a neighbourhood). My goal is to calculate the average annual solar irradiation (Wh/m2) on ...
7
votes
3answers
388 views

How do I create a raster randomly choosing a cell value from 2 or more overlapping rasters?

I'm using Arc 10. I want it to combine multiple rasters into one, always choosing randomly from the values of overlapping cells. I have an image that may explain this better:
6
votes
2answers
462 views

What are best practices to compare densities and locations between two sets of points?

I have two sets of point shapefiles. They represent two different customer groups for a retail store. Shapefile A represents online customers, Shapefile B represents in-store customers. What I ...
1
vote
2answers
504 views

arcpy.sa.Viewshed with OFFSETA

This is using ArcGIS10 arcpy with spatial analyst. I need to call Viewshed, but with an observer height set. I have tried using a Z-aware point feature set, but that only throws an error. I am ...
0
votes
1answer
160 views

Specific Spatial Analyst tools failing while running extension using ArcGIS server

I am having having trouble running ExtractValuesToPoints on a remote server machine running ArcGIS Server (with ArcInfo and Spatial Analyst installed). It fails and throws a standard COM error. I have ...
3
votes
1answer
402 views

Strange Behavior in Focal Statistics

I am trying to calculate the maximum value in a neighborhood on a raster using the Focal Statistics tool for Spatial Analyst in ArcGIS 10. Using python, I loop though several different radii, with ...
14
votes
4answers
1k views

Where can I find examples of fuzzy logic applications in ArcGIS?

The last ArcGIS version (10) includes two arctoolbox tools for fuzzy logic (Fuzzy Membership, and Fuzzy Overlay). Does anyone know where can I find some examples showing how they can be applied? ...
5
votes
1answer
226 views

How to find upstream - lateral and downstream zones around urban areas?

I've a DTM and a shapefile of built-up areas. For a fire risk model, I've to find (within a defined buffer zone) two zones around built-up areas: one that is above/higher and lateral and the other ...
5
votes
1answer
5k views

creating a dem from contours

I have a large set of contours that I received broken down into several different subsets. I have merged most of the subsets together creating a larger set of contours in three different files. I have ...
0
votes
0answers
538 views

Watershed / drainage network analysis; floating point or integer raster for input?

I am a little desperate to find a solution to my problem. As I have detailed in this post I am unable to create a detailed drainage network (and catchments) from high resolution LiDAR data. I think ...
13
votes
6answers
3k views

Methodology for creating accurate drainage networks (and catchments) from high resolution LiDAR DEM?

This is not the first time I've stumbled over this issue; it seems that I am unable to generate a correct drainage network model and the resulting catchments from full resolution (1m cells) LiDAR ...
3
votes
2answers
3k views

How do you set OFFSETA for a Viewshed in ArcGIS10?

How do I calculate height when attempting to do a viewshed analysis in ArcGIS10? I am able to create a viewshed analysis from a poly point file, however I need to calculate for the 80ft to 100ft tower ...
2
votes
0answers
428 views

Spatial Analyst Cell Statistics seems to give the wrong answer in ArcGIS 10.0

I have a script that calculates standard deviation for a list of grids using the Cell Statistics function in Spatial Analyst for ArcGIS 10.0 The syntax is this: stdevGrid = ...
4
votes
1answer
3k views

Thiessen Polygon delineation within a Feature

Greetings! I am trying to create Thiessen (Voronoi) polygons, based on points within a defined shapefile extent. The output should be inclusive to the feature. The output I receive now is the ...
4
votes
2answers
4k views

NoData in ArcGIS Spatial Analysis

When using Spatial Analyst I regularly have issues with NoData values cropping up in the data. Various tools appear to introduce NoData values regularly. These values then cause issues with other ...
6
votes
2answers
721 views

Process a raster with multiple geoprocessing tools in arcgis 10 using python - flow between processes

I'm writing a short python script that includes processing rasters with different geoprocessing tools in ArcGis 10, for example, the three processes below, is this best way to use multiple tools ...
3
votes
3answers
656 views

How do you produce a output table containing distances between mineral grains at various azimuthal directions?

I am using ArcGIS 10, the newest version and I am a senior at Western Carolina University and working on my senior thesis and the data set in which I have are images of mineral thin sections all ...
2
votes
3answers
932 views

How do you use Spatial Analyst Geoprocessing functions in ArcObjects in ArcGIS 10?

I'm trying to run some geoprocessing functions in ArcObjects. Some of the tools I want to use are part of the spatial analyst extension. In 9.3.1 it was fairly straightforward to follow the ...