HI Guys,
I'm trying to run a maxent model with two kind of datasource. two layers are shp converted to raster and then to ascii file. another one is on tiff file converted to grid and then to ascii file. My problem is the size of grid are not equal, so I'm not able to run maxen because have that error message.
Any help, comment or advise? I work with Arcgis, but I could also change to Qgis or R software.
Cheers!!
It sounds like you need to make your grids uniform first. The edge coordinates, as well as number of pixels in rows and columns of all environmental data-layers should be uniform. You may also wish to use a uniform input data-type (lets say only grids, or include all the environmental data in the ascii. That way Maxent will work.
You need to find the way way to transform vectors to grids in ArcGIS, and use grids instead of ascii. You may also transform all ESRI grids to Diva GIS grids using DIVA GIS (google it). Alternatively you may choose to convert grids to vectors, and then generate ascii. I personally prefer frids, because It helps better understand the data by visually comparing rasters. Please let me know if there are additional questions.
Hi Tigran!1
Yes, it was the problem, I solved with a mask and with all the files with the sizes according to the mask. Now I have other problem and it's with the Background point with data in all layers. I think that I have layer with 0 that means that, Have I transform the value 0 from my layers? Cheers!
Ricardo,
Do you mean you get an error message stating that background value is 0?
Hi Tigran,
I resolved the basic problem using arcgis and preparing all the data with same projection and same size of grid. Thanks!!
Hi again, I used a mask converted to grid and then to ascii using the follow tools:
Define projection
feature to raster
extract by mask
raster to ASCII
I realized that is possible to automate the process via building a model in Model Builder options. Cheers!!
Ricardo
Yes indeed, very good answers, and using model builder or scripting it in whichever way you prefer is the best approach, especially if you plan to "repeat this exercise another time".
However, be aware that you should also go a bit deeper in the "default settings" of these tools (both feature to raster as well as extract by mask), if you're extracting data for the same area at different times, or were to do it all over again, but at different resolutions. By going deeper I mean, ensure that parameters like "EXTENT" and "SNAP", just to name a few, are specified too. That is because, ESRI's default may not be what you want or realise, and are very data/object specific.
Feature to raster for example, is highly dependent on the resolution of your data, and extract by mask will give you different extents if you use the same feature but you extract different resolution rasters, and conversely, will extract a different extent if you generated a rasters from vectors without checking your SNAP to raster options in the first place.
May sound confusing, but will make sense if you look at these options and settings in details. Happy to provide even more details if necessary.
http://download.essc.org.ph/wcsp2012_sdm_workshop/data_prep.html#qgis-interface
Hi, I am having the same issue that all my layers are not in the same geographic dimensions. I am using ArcGIS pro and also used extract by mask and then converted to ascii but it still shows the same error.
- Badges
- Science topic
- Similar topics
- Engineering
- Modeling