using JR to export to bitmap, and scale question

[walleye3313]

hi david,

i'm still plugging away at my project! i promise to send you a copy to try out, really. you may recall that i am working with GPS/Sonar data and making bathymetric charts with the goal of being able to upload the data back to the GPS unit. right now i have everything working except converting the contour lines in the plot to coordinates. so....

here is my bit map question: when you set the dplot.plot command to save to a bitmap is the bitmap always the same size? or is the actual plot contained in the bitmap always the same(for example if i did not send a title that might make the whole image smaller but the plot area might still be the same)

the reason that i want to know is that i am going to take a plot from JR save it as a bitmap then i am going to scan the bit map bit by bit and record the bits which are black so that i can generate co-ordinates for each black bit. then i can use the coordinates in my app to do some cool stuff, well it will be cool to me at least.

now my scale question: supposing that the bitmap is always the same, can i set the scale of the plot at runtime? i am almost sure that i can, but have not really played to much in trying.


what i would like to have happen is to find that the bitmap is always some size, for example 500x500, then i could set the scale for x to be 100-600 and the scale for y to be 450-950 and i would have a 1 unit to 1 bit "conversion" to get coordinates. this is of course a simplistic example but i think you understand my idea.


one more thing that just popped into my mind: suppose i have some data that when sent to JR results in four contour lines one each at z=5, 10 15 and 20. but i only want to plot the z=10 line. can i simply reset the number of contour lines and the spacing in my command line so that i just get one contour and have it be the same as if i plotted the whole thing? my hunch is that yes i can, that i would be in essence just turning off the other lines.

thanks a bunch,
jerry

[DPlotAdmin]

Jerry,
To get the same size 2D plot every time, regardless of whether there's a title or axis labels or not, use [Size(1,width in inches,height in inches,1)]. Width and height are the size of the box around the plot, not including axis labels, numbers, titles, etc.

one more thing that just popped into my mind: suppose i have some data that when sent to JR results in four contour lines one each at z=5, 10 15 and 20. but i only want to plot the z=10 line. can i simply reset the number of contour lines and the spacing in my command line so that i just get one contour and have it be the same as if i plotted the whole thing? my hunch is that yes i can, that i would be in essence just turning off the other lines.

Use [ContourLevels(1,10,10)]

Looking forward to seeing your stuff, thanks.

[walleye3313]

Jerry,
To get the same size 2D plot every time, regardless of whether there's a title or axis labels or not, use [Size(1,width in inches,height in inches,1)]. Width and height are the size of the box around the plot, not including axis labels, numbers, titles, etc.

wow, that's cool. if i make the plot larger that will give me more bits and therefore a smaller "minor division" on the bit map then wouldn't it? for example if i made the bitmap 2x2 and the resulting scale was 1 bit = 1 foot and i then changed the size to 4x4 i would then have a scale of 1 bit=.5 foot.

is there a size limit for how big i can make the bitmap? the reason i ask is that i can only have 10,000 points in my finished file to upload(hardware limitation) and it would be optimum to have my points that i upload be about 1 meter apart. so i would like to be able to make the plot large enough to cause each bit to represent one meter on the surface of the earth. that way i can get the best possible resolution. i might also add a feature to my app that allows the user to accept a lower level of resolution there by enabling a larger portion of the earth to be shown in one file.

[quote}

Use [ContourLevels(1,10,10)]

Looking forward to seeing your stuff, thanks.[/quote]

that's what i thought, thanks

jerry

[DPlotAdmin]

if i make the plot larger that will give me more bits and therefore a smaller "minor division" on the bit map then wouldn't it?

Yes, that's correct.

Size limits: only the amount of memory you have. This shouldn't be a problem for any reasonable size, or even a... umm... unreasonable size.

[walleye3313]

great,

i'll have to do some experimenting with sizes to find just the right size to give me 1 meter between pixels.

thanks
jerry