topic Re: Converting ASCII UK wind speed file to a raster image in Data Management Questions

Converting ASCII UK wind speed file to a raster image

DanielBourne — Wed, 24 Aug 2011 14:49:45 GMT

Hi

Could any body help me convert the UK wind speed file provided by DECC found below to raster from ASCI. I have searched the forums and cant find any solution apart from phython which i dont know how to use, and evrytime i use the Tool in ARCmap it gives an error. Does any body have a solution or the UK wind speed data in raster format

http://www.decc.gov.uk/en/content/cms/meeting_energy/wind/windsp_databas/windsp_databas.aspx

hope someone can help

Re: Converting ASCII UK wind speed file to a raster image

EricRice — Wed, 24 Aug 2011 16:22:46 GMT

Greetings,

After reading the Windspeed Database Information Sheet I found the section you need...

�??The ETSU NOABL wind speed data is stored in ASCII (text) format. The file format
is ASCII, a simple text format. It may be that there is no dedicated function in any
particular GIS to read this file type. However, as the file type is simple and readable
by a number of different applications, (eg MS notepad, or Excel) that it should be
possible to import the data. The text file accompanying the ASCII files describes the
file format.�?�

Importing into ArcView
Open your ASCII file in Excel as semi-colon delimited data, delete header line and
first column and then save as a CSV comma delimited file.
Open this in a text editor such as Wordpad and Replace the 'semi-colon+space' with
a 'comma' and then delete carriage return at the end of the file and then add the
new header lines at the top of the file:

ncols 700
nrows 1300
xllcorner 0
yllcorner 0
cellsize 1000

Save it.

Next, in the file manager just delete the ".csv" suffix and replace with ".asc" and it is
ready for Import into ArcView if you turn on the "Spatial Analyst" extension.

My note would be, if you perform these steps, you don't need Spatial Analyst. ArcGIS reads .asc files as raster datasets assuming they have the header information outlined above. You will still have to define a spatial reference for the data, but I didn't see any information provided by the data provider as to what it is. You can see from their instructions that they are basically trying to get you to create an Esri Ascii Raster

Re: Converting ASCII UK wind speed file to a raster image

DanielBourne — Thu, 25 Aug 2011 08:07:25 GMT

Hi

I have completed everything you have suggested, and now it accepts the data into ARC as raster but makes the computer freeze. I am unsure of one part of your walk though;

'Open this in a text editor such as Wordpad and Replace the 'semi-colon+space' with
a 'comma' and then delete carriage return at the end of the file and then add the
new header lines at the top of the file'

the data was already comma separated and I don't know what a carriage return is, could you help me with this

Thanks
Daniel Bourne

Re: Converting ASCII UK wind speed file to a raster image

EricRice — Thu, 25 Aug 2011 13:26:02 GMT

Hi Daniel,

A carriage return is basically when someone presses the Enter key on the keyboard. As an example of what they are telling you to do.... Pretend you finished the last paragraph of a paper you were writing; then you hit Enter once,twice, 3 times to create empty lines at the end of the paragraph. It's those empty lines they want you to delete. Which can be hard because there isn't anything there for you to see to delete.

In terms of the data, the file I opened was not comma delimited. The data I downloaded looks like this.

9.4; 9.6; 8.2; 4.8; 3.5; 6.3; 7.1

So it is semi-colon + space delimited. They want you to do a find/replace in notepad to make it comma delimited. If your download was comma already you should be all set and just need to remove the carriage return and add the header.

Even though you shouldn't have to...I'm going to recommend that you run the ASCII to Raster tool once you have completed the steps.

Regards,
Eric

Re: Converting ASCII UK wind speed file to a raster image

DanielBourne — Thu, 25 Aug 2011 14:00:44 GMT

Hi

Im still having problems, would it be possible for me to email you my data and you have a look to see what im doing wrong. It makes arc freeze when added and wont convert from ASCII to raster

Re: Converting ASCII UK wind speed file to a raster image

EricRice — Thu, 25 Aug 2011 15:26:32 GMT

I downloaded the entire database from the website so I have the data. I have not gone through the steps to get it working; I simply read their instructions and passed on relevant points to you. I can try to get it working with the data I have and let you know, but to be totally honest and up front with you, I may not get to this problem today. If you have a deadline or urgent need to get it working I strongly encourage you to go through official channels. i.e. Esri Support or Esri UK Support if you're an international customer in the UK. If you're not in the UK, contact your local distributor. They should have analyst standing by that can provide immediate support.

I'll do my best to try and get the data working asap.

Eric

Re: Converting ASCII UK wind speed file to a raster image

EricRice — Fri, 26 Aug 2011 15:13:09 GMT

I am having the same issues as you with this data. I'm still looking for a solution. I also don't get why the instructions are telling us to do a find/replace to remove semi-colon + space and put in a comma, when after we save from Excel to CSV it becomes comma delimited. So I guess we can skip that step. 🙂

I'll keep you posted on any progress I make.

Note: I'm working with the orginal file named Speed10.asc.

Eric

Re: Converting ASCII UK wind speed file to a raster image

EricRice — Fri, 26 Aug 2011 15:45:52 GMT

Ok, got this one figured out. We need to delete the comma's and replace with spaces. I reviewed our own documentation for the Ascii to Raster tool and it basically says the cell values should be delimited by spaces. When I do that the data comes in fine even without running the Ascii to Raster tool. Like I said earlier, we support .asc files as raster datasets (when they are formatted properly). Here is a screenshot of the data.

Re: Converting ASCII UK wind speed file to a raster image

AshleyDurston — Tue, 10 Jul 2012 14:17:10 GMT

Hello.

I'm trying to do the same however I am a novice user of ArcGIS. I have tried to follow the steps but I just get completely confused. Are you able to send me the converted raster file or is the file too large?

Many Thanks,
Ashley

Re: Converting ASCII UK wind speed file to a raster image

AshleyDurston — Tue, 10 Jul 2012 14:48:45 GMT

Also, I don't understand what you mean when you say use the file manager to delete the file suffix and replace with ASC ??

Re: Converting ASCII UK wind speed file to a raster image

AshleyDurston — Tue, 10 Jul 2012 15:47:18 GMT

I can import the file as a raster now but its just a grey rectangle?

When it says delete first column I select column A in excel, hit delete but it just deletes the entire dataset?

Re: Converting ASCII UK wind speed file to a raster image

JeffreySwain — Wed, 11 Jul 2012 10:07:11 GMT

If it imported correctly and is a simple color, then you can apply a standard deviation stretch. You will have to generate statistics on the ascii file in order for the stretch to be applied. That is if the data made it in successfully after following the steps that Eric suggested.

Re: Converting ASCII UK wind speed file to a raster image

AshleyDurston — Thu, 12 Jul 2012 14:37:49 GMT

Tried creating statistics and applying the stretch but I just get a black rectangle with lots of white dots across it.

This is what my .asc file looks like:

ncols 700
nrows 1300
xllcorner 0
yllcorner 0
cellsize 1000
"( 0 1299) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0;"
"(100 1299) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0;"
"(200 1299) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0;"

is this correct? I've deleted the return carriage at the end also.

Ashley.

Re: Converting ASCII UK wind speed file to a raster image

SteveLynch — Thu, 12 Jul 2012 19:29:37 GMT

It is not the correct format, please see the help for the correct format.

You can't have strings and semicolons.

I.e
    NCOLS 3
    NROWS 2
    XLLCORNER 378922
    YLLCORNER 4072345
    CELLSIZE 30
    43 2 45
    35 45 65

Steve

Re: Converting ASCII UK wind speed file to a raster image

AshleyDurston — Thu, 12 Jul 2012 23:14:22 GMT

As I mentioned before I'm quite a novice with ArcGIS. This is for an important University project relating to wind farms in the UK. Am I able to send you the .ASC file for you to look at it and manipulate for use in ArcGIS? I've been trying for days to get this to work but have yet to be successful. Sorry to be a nuisance.

Ashley.

Re: Converting ASCII UK wind speed file to a raster image

AshleyDurston — Thu, 12 Jul 2012 23:22:50 GMT

In fact it's probably easier if I just give you the download link:

http://www.decc.gov.uk/en/content/cms/meeting_energy/wind/windsp_databas/windsp_databas.aspx

It's under 'Methods of Accessing the Windspeed Database' I'm using the file 'Speed25'

Again, Thank you.

Re: Converting ASCII UK wind speed file to a raster image

AshleyDurston — Fri, 13 Jul 2012 09:57:32 GMT

my asc file:

NCOLS 700
NROWS 1300
XLLCORNER 0
YLLCORNER 0
CELLSIZE 1000
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

this is what i get:

Re: Converting ASCII UK wind speed file to a raster image

SteveLynch — Fri, 13 Jul 2012 11:06:52 GMT

The text file must contain 700 * 1300 legit values from the 6th row onwards. It'll then use the first 700 for the northern most part of the raster and so on with the very southern most part coming from the very last 700 values.

It appears that you have non numeric values somewhere after the 6th row or you don't have 700*1300 values.

Steve

Re: Converting ASCII UK wind speed file to a raster image

alexdoney — Tue, 06 Nov 2012 11:19:52 GMT

hi im currently trying to convert this file into a raster file but i am stuck. I tried the process on here but i can seem to get it to work when i put it into Arc scene it freezes and crashes and i dont know what im doing wrong. Isit possible for anyone to send me the files they used that work because i really need the data to use on my geography dissertation. thanks alex