Latest Contributions by PiyaliKundu

‎12-17-2015

Hello all, I realized that I had reprojected all the tiles prior to mosaicking them into the global dataset (since the VCF dataset is in 500m x 500m and Cylindrical_Equal_Area). This must have sped up the process a lot and been much less intensive. Thanks all for your efforts and replies.

‎12-17-2015

Hello Chad, Thank you for your reply. I have tried using a mosaic dataset and was actually able to make it successfully, but it has caused ArcGIS to freeze and crash anytime I have used it as an input dataset in Raster Calculator. I even let the calc run in the foreground overnight and saw that there was 0% progress I'm not sure if this is because of my computer being somewhat old and slowed down due to the O365 migration or some other reason.

‎12-17-2015

Hello Luke, Thank you for your response. We are trying to use the Hansen/GFC loss data to provide an estimate on global deforestation using an altered version of the VCF forest cover dataset. After mosaicking the loss tiles, we used the following calc in Raster Calculator to add the deforestation to the forest cover layer (I'm also including the range of values for each raster): (Deforestation [Values: 0 (NoData),1(deforestation)] x 100) + Forest cover [Values: 31->80 (% forest cover)]. Any values >=100 were reclassified as loss. Finally, the overall product was resampled to 1km x 1km and reprojected to continue doing some other analyses (this is just the first part of a bigger problem we are trying to solve). I had successfully completed all of this before and verified that the files had processed correctly, but I recently lost my datasets due to an external hard drive crash. In between the first attempt at this analysis and the HD crash, our institution migrated to Office 365, which to my understanding involves numerous processes running in the background, and my computer has performed significantly slower ever since. Believe it or not, after removing the extraneous ocean tiles from the GFC dataset, I was able to mosaic the loss tiles within 1-2 hours; all the mosaicked data lined up with the data in the original tiles. While my computer is nothing terribly special--a fairly old Dell Latitude E6410 laptop with an i7 processor and only 4GB of RAM--it actually regularly outperformed several of our other desktop computers. I never imagined this would be such an issue to rerun!

‎12-15-2015

Hello, I am trying to mosaic the 500+ raster tiles of the Hansen/UMD 2015 GFC forest loss dataset (30m x 30m cell size) into one global dataset and am trying to figure out the most efficient and least time-consuming process to do this. The end result does not necessarily need to be one raster (i.e., using Mosaic to New Raster tool) and I am open to utilizing Mosaic datasets, as long as I can utilize the final product/composite file in Raster Calculator. I do not have much experience using Mosaic datasets prior to this task. So far I have tried the following methods, but each one seems to be very time consuming (several hours to days) and have resulted in numerous crashes: - Input all the raster tiles into a Mosaic dataset -- this method seems to be taking several hours just to input all the rasters into the mosaic dataset. The first time I ran this, it took about 10 minutes to input all the rasters, but they were not rendering properly. The second time I attempted this, the script is indicating that there are some 11,000 files being generated for the mosaic dataset and it will take several hours to accomplish. - Isolate only the tiles that actually have deforestation values (eliminate tiles over the ocean to reduce # of tiles that need to be processed overall) and then mosaic them -- for this, I thought the best way would be to build raster attribute tables for each, and use the Unique Values symbology to delete rasters with only Value = 0 (No Data), then mosaic the remaining files. I am building the attribute tables for each raster though a simple model in Model Builder, but still, the process is very time-intensive. In addition, I'm not sure how to automate changing the symbology from Stretched (default when you add data to the TOC) to Unique Values and have been doing it manually. In this case, I don't think that batching an Apply Symbology approach would work, because I want to isolate those rasters that have only No Data values to delete them. (Batching the Apply Symbology would make each raster seem like it has values of 0 and 1 (or only 0 values, depending on which raster is used), which would result in more work for me to fix it.) I have also tried just a straight Mosaic to New Raster with all 500 rasters, but it did not complete even after 3 days of processing. I was also considering deleting according to file size, however, there are instances in which the smaller sized files have values of 1/contain deforestation data, so I can't use that kind of blanket approach. Does anyone have any suggestions on how to handle large numbers of rasters in one go? Or, does anyone know of a script to eliminate the GFC tiles that are over ocean only / eliminate the tiles that contain no data?

‎05-28-2015

There was no specific reason other than wanting to get familiar with the newer Python version, but say if someone had other files already written in 3.4 before trying to run arcpy? Would they have to delete Python 3.4 in order to get arcpy to work?

‎05-28-2015

I resolved the problem by uninstalling Python 3.4. I'm not sure if there's a workaround for also having Python 3.4 on your machine and running arcpy, but I wasn't able to get it to work for some reason. That's kind of a shame. What if someone had other Python scripts already written in Python 3.4? Would they have to delete Python 3.4 and revert back to 2.7?

‎05-28-2015

Hello all, I have been running into some configuration errors while trying to import arcpy module into a simple Python script file, and I suspect that the errors might have something to do with the environment variables settings. Prior to the error above, I was running into a "ImportError: No module named 'arcpy'" error, which was related to incorrect environment variables. I have both Python 2.7 and Python 3.4 installed on my computer, and I would like to be able to use both of them in my code, but I'm not sure if that's possible. Operating System: Windows 7 Application: ArcGIS for Desktop version 10.2.1 Path to ArcGIS: C:\Program Files (x86)\ArcGIS\Desktop10.2 Path to Python 2.7: C:\Python27 Path to Python 3.4: C:\Python34 Python IDE: PyCharm Community Edition 4.5.1 Environment Variables: PATH: C:\Python27\;C:\Python34\;D:\Documents and Settings\pkundu\AppData\Roaming\npm;C:\Program Files (x86)\Java\jre7\bin PYTHONPATH: C:\Program Files (x86)\ArcGIS\Desktop10.2\bin;C:\Program Files (x86)\ArcGIS\Desktop10.2\arcpy;C:\Program Files (x86)\ArcGIS\Desktop10.2\ArcToolbox\Script When I try to run a very basic command: import arcpy I get the following error: Traceback (most recent call last): File "D:/Documents and Settings/pkundu/Desktop/pytest/testpy2.py", line 6, in <module> import arcpy File "C:\Program Files (x86)\ArcGIS\Desktop10.2\arcpy\arcpy\__init__.py", line 21, in <module> from arcpy.geoprocessing import gp File "C:\Program Files (x86)\ArcGIS\Desktop10.2\arcpy\arcpy\geoprocessing\__init__.py", line 14, in <module> from _base import * ImportError: No module named '_base' Process finished with exit code 1 Would greatly appreciate a solution to this problem as I have not seen any other posts regarding this error. Most other posts have to do with the "ImportError: No module named 'arcpy'" error I was experiencing before I edited my environment variables to the ones listed above. When I followed the error code, I found that the geoprocessing folder contains both the "__init__.py" file and the "_base.py" file.

‎04-10-2015

This may be a very simple question, but I have not found the answer after searching for forever, and all the code snippets I have used have been based off of the FID, which I DO NOT WANT. I have a long list of features which I would like to ID sequentially, but not based off of the FID at all! I just want them to go down the field like (1,2,3,4, etc.). I have tried using the following snippet for Python which was supplied by ESRI, but it doesn't work as it essentially just adds 1 to the FID: Pre-Logic Code: rec=0 def autoIncrement(): global rec pStart = 1 pInterval = 1 if (rec == 0): rec = pStart else: rec += pInterval return rec Code Block: autoIncrement() Source: 38517 - Create sequential numbers in a field using Python in the Field Calculator

‎11-02-2014

Hello all, I used to have a student license to ArcGIS 10.2 on my Mac through Parallels 9, which has suddenly stopped working. I just bought a second (Windows!) computer in hopes that I can transfer my student license onto the new computer. However, is there a way to do this without having to run the License Manager on the original machine? I cannot access the virtual machine because Parallels won't open. (Gives an error.) I tried calling support but I guess there is no tech support over the weekend. Thanks!

‎09-12-2014

Thanks Timothy! I'll be honest, I don't think I know how to post anything correctly in this forum haha. I usually just go to the "Create" tab at the top, then go to "Discussion" and post a discussion. Where it posts to, I never know. In response to your answer, I would think that is the case, but if the buffer causes no geometry, the feature is usually just skipped. I reran the same -100m buffer using a simplified version of the forest extent, and the process worked. It skipped several thousands of tiny forest fragments in the process, but that was expected. The original forest extent shapefile I was working with (and was mentioning in my first post) was one that I created by converting the original raster to a polygon and UNCHECKING the simplify polygon box, because I wanted the polygon forest layer to mirror the original raster as close as possible. Maybe it's possible that the shapes are just too complex for ArcGIS to handle a negative/interior buffer? It was able to use the unsimplified forest extent to do a +1km buffer, however.

‎09-11-2014

Hey all, I have a polygon shapefile of a forest extent containing approximately 2,200 forest fragment features that I would like to place a -100m internal buffer on to find the fragment core sizes. The largest forest fragment is about 450,000 ha. However, I keep running into an "Error 999999: Error executing function" every time I try to run the buffer tool. I tried running the tool with some individual fragments and it seems to work for the smaller ones (around 1,000-2,000 ha). Unfortunately I can't access the log file because I don't have administrative rights. I have tried making sure the processing extent is correct (I feel like for buffer, the "Union of Inputs" should be a correct option since there's only one input, but I have also specified the extent of the forest shapefile just in case). I have also tried changing the projection--but nothing seems to work. In the end, I have to stop because my computer keeps running out of memory. I have to restart ArcGIS after the first attempt to buffer fails because the second attempt will also fail because there is not enough memory. Help is appreciated, thanks!

‎07-21-2014

Hi Dan (and Timothy Hales ), I tried using a Mosaic Dataset today, and I'm a bit confused. It seems like it doesn't doesn't display the actual rasters that I loaded into it (the "Image" category is basically irrelevant, as it's not displaying the data). Do I treat the mosaic dataset as I would a newly mosaic-ed layer? As in, when I go to tabulate areas, would I drag the mosaic dataset into the tool and it will tabulate the area of the zone like a normal raster layer? Or do I need to project my rasters before loading them into the mosaic dataset? (I thought we are allowed to change the projection within the Create Mosaic Dataset tool.) Thanks for your help!

‎07-17-2014

Hey all, I have a number of Global Forest Watch raster tiles that I need to reproject and mosaic quickly. So far I have been using the Mosaic to New Raster tool to accomplish both tasks in one step, however it takes a whopping +30 minutes for me to mosaic and reproject just two raster tiles. Is there a way in which this could be accomplished faster, either by using a different tool or by getting the Mosaic to New Raster tool to process faster? If done separately, it takes about the same time (about 4-5 minutes to reproject an individual raster tile, and 15 minutes to mosaic them together). I have also tried the method of creating a raster catalog and then turning the catalog into a raster dataset, but I was wondering if there was a way that required less steps/less files created for the inbetween phases. Thanks, P

‎05-23-2014

Managed to somewhat solve the answer to my problem. ArcGIS 10.2 allows users to input Excel table elements. However, ArcGIS has somewhat messed up the preview aspect of this function. The table looks fine in print preview, but not in layout mode. If anyone has other suggestions, I'd be happy to hear them.

‎05-23-2014

Hey all, I'm trying to format a particular section of my legend into a table. An image of the legend is attached to this message for your viewing. I am trying to format the key for the Ecological-Economic Zoning section into a table with 3 columns, the first column with the color, the second column with the description, and the third column with a set of area measurements. I do not have the Production Mapping extension to create the dynamic table elements. Is there a way to make just a simple table to display this information? Thanks, image[ATTACH=CONFIG]34039[/ATTACH]

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Date Last Visited	‎11-11-2020 02:23 AM

My Ideas

Latest Contributions by PiyaliKundu

Re: how to handle 500+ Hansen/Global Forest Change raster tiles

Re: how to handle 500+ Hansen/Global Forest Change raster tiles

Re: how to handle 500+ Hansen/Global Forest Change raster tiles

how to handle 500+ Hansen/Global Forest Change raster tiles

Re: ImportError: No module named '_base' when importing arcpy

Re: ImportError: No module named '_base' when importing arcpy

ImportError: No module named '_base' when importing arcpy

how to sequentially number a field in Field Calculator (NOT BASED ON FID)

migrating arcgis 10.2 license without original machine

Re: Experiencing "Error 999999: Error executing function" for a simple buffer task

Experiencing "Error 999999: Error executing function" for a simple buffer task

Re: Faster way to mosaic rasters

Faster way to mosaic rasters

Re: How to create a simple table (for legend) in ArcGIS 10.2

How to create a simple table (for legend) in ArcGIS 10.2